To provide an abnormality detecting device capable of detecting an abnormality of a plurality of circuits to be inspected with no switching operation or switching means.

An abnormality detecting device 10 comprises a resistance measuring device 13 for measuring electric resistance value of a parallel test circuit 12 where a plurality of test unit circuit parts 16 of the same electric resistance value are connected each other, a judging circuit 18 for judging whether abnormality has occurred at the test unit circuit part 16 based on the resistance value measured with the resistance measuring device, and a display part 19. The judging circuit 18 compares a calculation part 18a for calculating a variation amount of measured resistance values with the resistance measuring device 13, to the calculation result of the calculation part, and to a total tolerance difference α which is a threshold value. When the variation amount is judged to have exceeded that total tolerance difference α, the display part 19 displays that an abnormality has occurred.