PURPOSE: To obtain an abnormality detection device for a photosemiconductor capable of detecting not only permanent abnormality of a photosemiconductor but also tentative abnormality.

CONSTITUTION: An abnormality detection device for photosemiconductor has a detection part 100, an RS flip-flop circuit 104 to be a memory and a luminous diode 106 for discriminating an abnormal photosemiconductor element to be an indication part. The detection part 100 detects the change in the drive current for tested photosemiconductor element 103, that is, the shield of normal direction current IF and outputs a high level voltage signal as detected signal 100a to the RS flip-flop circuit 104. The RS flip-flop circuit 104 memorizes that the detected signal 100a is output from the detection part 100, and outputs its high level voltage signal as indication signal 104a indicating the shield of the normal direction current IF of the tested photosemiconductor element 103 to the luminous diode 106 for discriminating an abnormal photosemiconductor element.