To provide a device for detecting urination or defecation capable of quickly detecting urination and defecation of a subject such as a bed-ridden person when the subject urinates or defecates, and an automatic disposal device for urine or excrement capable of automatically disposing urine or excrement.

The device for detecting urination or defecation comprises an image detecting means disposed near the urine evacuation part or the excrement evacuation part of the subject, and a determining means for determining the start of urination or defecation based on a signal from the image detecting means. The automatic disposal device for urine or excrement comprises a blocking part for covering the image detecting means, the determining means and the urine evacuation part or the excrement evacuation part of the subject in such a way as to block air flow to the outside, a tank connected to the blocking part in such a way that air and urine or excrement can flow, a suction part for sucking the urine or excrement from the blocking part into the tank, and a suction control part for controlling the suction part based on the signal from the determining means.