A columnar conductor 7b is provide in such a way as to be located concentrically with the columnar conductor 7 in the inner layer of the multilayer substrate 3. A columnar conductor 9aa, a columnar conductor 9ba, a columnar conductor 9ca, a columnar conductor 9da, a columnar conductor 9ea, a columnar conductor 9fa, a columnar conductor 9ha, a columnar conductor 9ia, a columnar conductor 9ja, a columnar conductor 9ka and a columnar conductor 9la, which are shown in FIG. 4, are provided in such a way as to penetrate the multilayer substrate 3 and to surround the columnar conductor 7b. Each of the columnar conductors 9aa, 9ba, 9ca, 9da, 9ea, 9fa, 9ha, 9ia, 9ja, 9ka and 9la is electrically connected to the ground plane 5d on the uppermost surface of the multilayer substrate 3, and is electrically connected to the ground plane 5f on the lowermost surface of the multilayer substrate 3.

A strip line 10 is a transmission line extending from an outer peripheral portion of the multilayer substrate 3 to the inside thereof. One end portion of the strip line 10, the end portion extending toward the inside of the multilayer substrate 3, is electrically connected to the columnar conductor 7b. In addition, the other end portion of the strip line 10 is electrically connected to an amplifier 102 which a high frequency circuit 101 includes.