To provide clean underpants enabling a patient to relieve nature as it is even in a state lying on his back on a bed.

Urine and feces are washed off from the clean underpants put on the patient as they are even if the patient lies on his back on a bed. Thereafter, the clear pants are dried by hot air. Sewers are arranged on and under the floor of a room, and urine and feces are allowed to flow to the sewers.