PURPOSE: To provide a wiring tester dealing with any kind of wiring, by connecting a diode to each of input terminals of exclusive OR circuits, and using the two terminals of each exclusive OR circuit as a test terminal and a reference terminal respectively.

CONSTITUTION: Diodes 2 are connected to input terminals of exclusive OR circuits 1, and the input terminals of the circuits 1 act as test terminals A1WA4, and reference terminals B1WB4. Also, cathodes of the diodes 2 act as pulse input terminals C1WC4, and failure detection signals are given at output terminals Y1WY4. Therefore, distinction between open H and signal level H, and distinction between a short circuit of input terminals A1-A2 for two circuits 1 in open H state and input terminals B1, B2 that exist independently are made possible. Thus, by connecting a wiring to be checked to the test terminals A1WA4, and a nonfailure wiring to reference terminals B1WB4, all of wiring faults, wiring errors, excessive wiring and short circuits can be detected.