An excretion detection device 10 comprises: electrode unit 120 configured by using materials with different ionization tendencies; a neutralizer retention unit 112 configured to retain a neutralizer for reducing the hydrogen ion index of the bodily waste; and an active tag 150 configured to notify the excretion from the living body to outside the excretion detection device. The electrode unite 120 is provided at a position where the electrode unit can be in contact with the bodily waste. The neutralizer retention unit 112 is provided at a position where the neutralizer can be in contact with the bodily waste.