PURPOSE: To improve a productivity without requiring to attach later a capacitor for dealing with a high frequency noise by connecting the capacitor for removing the high frequency noise to an output terminal section of an FET and incorporating the FET and the capacitor in a barrel like insulating body.

CONSTITUTION: A capacitor 11 for dealing with a high frequency noise is connected and fixed to an output lead 8b of an FET 8 on a print substrate 9 through a soldering section 9a or the like. It is difficult to receive an induced noise or the like since the capacitor is inside a case 2 and when soldering the output lead line or the like later, it is not molten nor disengaged. Since the capacitor 11 is assembled inside, it can be treated as the amplifier block substantially as the convention, the productivity is not lowered. As the capacitor 11, a compact cylindrical porcelain capacitor having a lead may be preferably used.