PURPOSE: To enable the determination of a faulty article in a short time, by providing a pulse inspecting circuit which determines at each voltage level whether the pulse width and phase of a pulse to be inspected is within standards or not.

CONSTITUTION: The same pulse signal is inputted to a standard circuit 2 and a circuit 3 to be inspected from a control circuit 1. The circuits 2 and 3 have the same circuit construction, and composite pulse signals are outputted from output terminals of the two circuits. The composite pulses outputted from the circuits 2 and 3 are inputted to first and second level inspecting circuits 4 and 5 respectively, and they are compared with a normal voltage at each voltage level in a window comparator and separated. Out of output signals of the circuits 4 and 5, the signals separated at the same voltage level are subsequently inputted to the same pulse inspecting circuit 6 (6L, 6M, 6H). In the circuit 6, the signals are compared with a pulse to be inspected on the output side of the circuit 3 to be inspected, on the basis of a standard pulse on the output side of the standard circuit 2, and it is inspected whether the width and phase of the pulse to be inspected are within inspection standards or not. In this way, a faulty article can be determined in a short time.