What is claimed is:1. An electronic device comprising:a semiconductor component including a first terminal to or from which a first signal is input or output; anda wiring board including an upper surface, on which the semiconductor component is mounted such that the upper surface faces the semiconductor component, and a lower surface opposite the upper surface,wherein the wiring board includes:a first board terminal which is formed in a first wiring layer and is electrically connected to the first terminal;a first wire which is formed in the first wiring layer and is electrically connected to the first board terminal;a first conductor pattern which is formed in a second wiring layer different from the first wiring layer and is electrically connected to the first wire via a first via wire; anda second conductor pattern which is formed in a third wiring layer different from the first wiring layer and the second wiring layer and is supplied with a first fixed potential,wherein the first wiring layer is located closer to the upper surface than the lower surface in a cross-sectional view,wherein the second wiring layer is located between the first wiring layer and the lower surface in the cross-sectional view,wherein the first conductor pattern and the second conductor pattern face each other with an insulating layer interposed therebetween, andwherein an area of a region where the first conductor pattern and the second conductor pattern face each other is larger than an area of the first wire in a plan view.2. The electronic device according to claim 1,wherein, in a thickness direction of the wiring board, the third wiring layer is located between the second wiring layer and the first wiring layer in the cross-sectional view.3. The electronic device according to claim 2,wherein the semiconductor component includes a second terminal through which a current different from the first signal flows,wherein the wiring board includes a second board terminal which is formed in the same layer where the first board terminal is formed and which is connected to the second terminal, andwherein, in the plan view, the first conductor pattern overlaps with the second board terminal.4. The electronic device according to claim 2,wherein the first wire and the second conductor pattern face each other with an insulating layer interposed therebetween.5. The electronic device according to claim 1,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire, andwherein, in the plan view, the first conductor pattern overlaps with the first extending portion of the first wire.6. The electronic device according to claim 1,wherein the first signal is an input signal input to a first circuit of the semiconductor component via the first terminal,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire,wherein the first via land portion is located between the first extending portion and the first board terminal in the plan view, andwherein, in the plan view, a separation distance between the first board terminal and the first via land portion is shorter than a distance over which the first extending portion extends.7. The electronic device according to claim 1,wherein an electronic component connected to the first wire is mounted on the wiring board,wherein the first signal is a signal which is output from the electronic component and is input to a first circuit of the semiconductor component via the first terminal,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire,wherein the first via land portion is located between the first extending portion and the first board terminal in the plan view, andwherein, in the plan view, a separation distance between the electronic component and the first via land portion is longer than a separation distance between the first board terminal and the first via land portion.8. The electronic device according to claim 1,wherein the first signal is an output signal output from a first circuit of the semiconductor component via the first terminal,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire, andwherein the first extending portion is located between the first via land portion and the first board terminal in the plan view.9. The electronic device according to claim 1,wherein an electronic component connected to the first wire is mounted on the wiring board,wherein the first signal is a signal which is output from a first circuit of the semiconductor component via the first terminal and is input to the electronic component,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire,wherein the first extending portion is located between the first via land portion and the first board terminal in the plan view, andwherein, in the plan view, a separation distance between the first terminal and the first via land portion is longer than a separation distance between the electronic component and the first via land portion.10. The electronic device according to claim 1,wherein the first wire includes a first extending portion extending in a first direction,wherein, in the plan view, the first conductor pattern has a first longer side extending in the first direction, and a second longer side located opposite to the first longer side, andwherein, in a second direction crossing the first direction, a separation distance between the first longer side and the second longer side is longer than a width of the first extending portion of the first wire.11. The electronic device according to claim 10,wherein a length of the first extending portion of the first wire in the first direction is longer than the separation distance between the first longer side and the second longer side.12. The electronic device according to claim 1,wherein the wiring board includes:a plurality of the first conductor patterns connected to the first wire via the first via wire and formed in different wiring layers from one another; anda plurality of the second conductor patterns formed in different wiring layers from one another,wherein each of the plurality of the first conductor patterns and each of the plurality of the second conductor patterns are formed in different wiring layers with each other, andwherein each of the plurality of the first conductor patterns faces any of the plurality of the second conductor patterns with the insulating layer interposed therebetween.13. An electronic device comprising:a semiconductor component including an electric power conversion circuit, and a first terminal which is an output terminal connected to the electric power conversion circuit; anda wiring board including an upper surface on which the semiconductor component is mounted such that the upper surface faces the semiconductor component, and a lower surface opposite the upper surface,wherein the wiring board includes:a first board terminal which is formed in a first wiring layer and is electrically connected to the first terminal;a first wire formed in the first wiring layer and electrically connected to the first board terminal;a first conductor pattern formed in a second wiring layer different from the first wiring layer and electrically connected to the first wire via a first via wire; anda second conductor pattern formed in a third wiring layer different from the first wiring layer and the second wiring layer and supplied with a first fixed potential,wherein the first wiring layer is located closer to the upper surface than the lower surface in a cross-sectional view,wherein the second wiring layer is located between the first wiring layer and the lower surface in the cross-sectional view,wherein the first conductor pattern and the second conductor pattern face each other with an insulating layer interposed therebetween,wherein an area of a region where the first conductor pattern and the second conductor pattern face each other is larger than an area of the first wire,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire, andwherein the first extending portion is located between the first via land portion and the first board terminal in a plan view.14. An electronic device comprising:an electronic component including a first terminal from which a first potential is output, and a second terminal from which a second potential different from the first potential is output;a semiconductor component to which the first potential and the second potential are input;a first condenser component including a first electrode electrically connected to the first terminal, and a second electrode electrically connected to the second terminal; anda wiring board on which the electronic component, the semiconductor component, and the first condenser component are mounted,wherein the wiring board includes:a first board terminal connected to the first terminal;a first wire formed in a first wiring layer and electrically connected to the first board terminal;a first conductor pattern formed in a second wiring layer different from the first wiring layer and electrically connected to the first wire via a first via wire; anda second conductor pattern formed in a third wiring layer different from the first wiring layer and the second wiring layer and supplied with a first fixed potential,wherein the first conductor pattern and the second conductor pattern face each other with an insulating layer interposed therebetween,wherein an area of a region where the first conductor pattern and the second conductor pattern face each other is larger than an area of the first wire,wherein the first wire includes a first extending portion extending in a first direction, and a first via land portion connected to the first via wire, andwherein, in plan view, the first extending portion is located between the first via land portion and the first board terminal, and the first via land portion is located between the first electrode of the first condenser component and the first extending portion of the first wire.15. The electronic device of claim 14,wherein the wiring board has an upper surface and a lower surface opposite the upper surface,wherein the electronic component and the semiconductor component are mounted such that the upper surface faces the electronic component and the semiconductor component,wherein the first condenser component is mounted such that the lower surface faces the first condenser component,wherein the first board terminal is formed in the first wiring layer and is electrically connected to the first terminal,wherein the first wiring layer is located closer to the upper surface than the lower surface in a cross-sectional view, andwherein the second wiring layer is located between the first wiring layer and the lower surface in the cross-sectional view.16. The electronic device of claim 14, wherein the first wire electrically connects the semiconductor device to the electronic component, such that said first potential is input to the semiconductor component from the electronic component via the first wire.17. The electronic device according to claim 1, wherein the first conductor pattern and the second conductor pattern form a capacitor of a noise filter circuit.18. The electronic device according to claim 1, wherein the first signal is different from the first fixed potential.19. The electronic device according to claim 1,wherein a noise filter circuit is formed by at least the first wire, the first conductor pattern, and the second conductor pattern, andthe noise filter circuit is configured to reduce noise in said first signal.20. The electronic device according to claim 1, wherein the second conductor pattern is configured as a shield conductor layer that shields the first conductor pattern from electromagnetic radiation from the first wiring layer.