PROBLEM TO BE SOLVED: To provide a pet toilet, usable from pet infancy to the period of its growth and thereafter.SOLUTION: The pet toilet includes: an outer container 10 and an inner container 20, wherein the sidewall 12a of the outer container 10 is provided with an outer side low sidewall section 15 with low sidewall height, while the sidewall 22a of the inner container 20 is provided with an inner side low sidewall section 25 with low sidewall height； the outer container 10 and the inner container 20 are relatively movable. In this toilet, by laying the inner container 20 in the outer container 10 with the respective positions of the outer side low sidewall section 15 and the inner side low sidewall section 25 made coincide with each other, a pet entry section 2 lower in height than the adjoining sidewall 3 is ensured to form； while, by laying the inner container 20 in the outer container10 so as not to make the respective positions of the outer side low sidewall section 15 and the inner side low sidewall section 25 coincide with each other, the outer side low sidewall section 15 is closed by the sidewall of the inner container 20 and the inner side low sidewall section 25 is closed by the sidewall of the outer container 10.
