The first insulating layer 211a may have a thickness greater than those of the second insulating layer 211b and the third insulating layer 211c. The first insulating layer 211a may be basically relatively thick in order to maintain rigidity, and the second insulating layer 211b and the third insulating layer 211c may be introduced in order to form a larger number of wiring layers 212c and 212d. The first insulating layer 211a may include an insulating material different from those of the second insulating layer 211b and the third insulating layer 211c. For example, the first insulating layer 211a may be, for example, prepreg including a core material, a filler, and an insulating resin, and the second insulating layer 211b and the third insulating layer 211c may be an ABF or a PID film including a filler and an insulating resin. However, the materials of the first insulating layer 211a and the second and third insulating layers 211b and 211c are not limited thereto.