Animal litter box

An animal litter box includes: a tray housing including a urine passage portion and an insertion opening; and a tray including an absorbent-body placement surface. The urine passage portion has holes through which urine pass downward. The insertion opening is formed in a front surface of the tray housing. On the absorbent-body placement surface, an absorbent body for absorbing urine that has passed through the holes is placed. The tray is housed in the tray housing from the insertion opening in such a way that the tray is capable of being pulled out forward. The tray is capable of being housed in the tray housing with an orientation of the tray in the front-back direction reversed. The tray includes an identification portion in a part of the tray other than the absorbent-body placement surface, and the identification portion is for identifying one side and another side in the front-back direction.