A pet toilet 10 having a toilet box 13, a drainboard 14 partitioning the toilet box into an upper compartment and a lower compartment, an excreta treating material 15 laid in the upper compartment, and an urine absorbent member 11 laid in the lower compartment. The drainboard is an integral structure formed of a plurality of longitudinally extending ribs 17 spaced parallel with each other and a plurality of transversely extending ribs 18a and 18b intersecting the longitudinally extending ribs 17 and spaced parallel with each other to have drain holes 12. Each drain hole 12 has a longitudinal dimension S2 at least twice its transverse dimension S1. The transversely extending ribs include ribs 18a with a smaller height H1 from the drainboard surface 14a downward and ribs 18b with a larger height H2 from the drainboard surface 14a downward, the ribs 18a and the ribs 18b alternating with each other.