Animal litter box

An animal litter box having a transverse direction, a longitudinal direction and a vertical direction and including a lower container having an upper opening, an upper side cover placed on 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 to define a receiving space in such a manner that liquid inflows into the receiving space, wherein:

• 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,
• the excrement tray has a bottom wall configured in a rectangle as seen in its planar view and side walls formed along a peripheral edge composed of four sides of the bottom wall and adapted to be put in contact with flap extending along a peripheral edge of an absorbent structure, and
• a pair of the side walls is formed in a tilted manner so as to be gradually distanced from each other as the side walls extend upward.