To sufficiently prevent leakage of a radio wave end intrusion of power noise by completely shielding an amplifier circuit and a power supply circuit.

A case main body 2 whose circumferential wall is formed with plug mount holes 1 and a partition wall 5 that parts the inside of the case 2 into an amplifier section container chamber 3 and a power supply section container chamber 4 without a gap are formed integrally, and the amplifier section container chamber 3 containing an amplifier section and the power supply section container chamber 4 containing the power supply section are closely covered by one or separate covers 6. Then threaded holes are adopted for the plug mount holes 1 made to the circumferential wall of the case main body 2.