PURPOSE: To effect speedy detection of any fault in information transmitting system of vehicle side or ground side by providing for control apparatus of vehicle side and ground side with test circuit for detecting fault thereof.

CONSTITUTION: When push-button type switches 31, 32, 33 for transmitting test signals are sequentially operated on the ground side, frequency signals f1, f2, f3 are transmitted to vehicle 1 so that relays 16, 17, 18 on the vehicle 1 are actuated in sequence. Signal reception confirmating relay 25 repeats continuously its on-off action so that when its contact is opend, position signal transmitted from vehicle 1 is interrupted at each time of operation of the switches 31, 32, 33. As a result, it can be found out that any part of information transmitting system has been faulty by deciding whether position signal of the vehicle 1 on the ground side is interrupted or not synchronously with the operation of the switches 31, 32, and 33.