PURPOSE: To detect effectively a current induced on a car body due to a broadcast wave by providing a high frequency pickup along the surface of a trunk hinge of an automobile.

CONSTITUTION: The high frequency pickup 32 is fixed to an outside along a lengthwise direction of the trunk hinge 34, i.e., the trunk room side and a loop antenna 44 provided in the inside is arranged so that its lengthwise direction is made coincident with the lengthwise direction of the hinge 34. Since the hinge 34 is placed remotely from the engine, the effect of noise from the car body is hardly given. Thus, the surface current flowing to the hinge 34 is caught to the loop antenna 44 with high efficiency surely. Thus,the current induced on the car body due to the broadcast wave is detected effectively.