An animal litter box has a transverse direction, a longitudinal direction and a vertical direction and includes a lower container having an opening at an upper end thereof and allocated on the lower side, an upper side cover allocated above the lower container and a liquid passable litter tray interposed between the upper side cover and the lower container and cooperating with the lower container to close the opening. The lower container has an excrement tray provided so as to be manually movable in the longitudinal direction between a put-in position at which the excrement tray is set within the receiving space below the liquid passable litter tray and a drawn out position outside the receiving space and an end opening through which the excrement tray is put into or drawn out from the receiving space.
