An excrement detection sensor in which two pairs of conductors 1, 2 and 3, 4 are formed between a carrier body 6 and a coating body 7 both having water-proof property and insulating property, wherein the cover body is formed with an urine introduction port 8 correlating the paired conductors and with a faeces introduction port 9 correlating the other paired conductors, and when urine enters into the urine introduction ports, the one pair of the conductors are short-circuited and when faeces enters into the faeces introduction ports, the other one pair of the conductors are short-circuited, whereby the urination and the evacuation can be distinctively detected.