To provide a tank equipment not being required to take any special measure to cope with watering on a circuit substrate, thinning the thickness of an outer case to the approximately same extent as that of a low tank and, at the same time, mounting a hinge of a toilet cover on the lowest position to the utmost.

A tank equipment device such as a low tank 9 or the like is installed on the upper surface in the rear of a Western-style toilet A, an outer case 13 for covering the tank equipment is provided, and in the tank equipment mounting a circuit substrate 11 to the inside of the tank equipment, a circuit substrate mounting section is provided to the low tank side inside of the tank equipment in the direction of the depth, and the lower part of the circuit substrate 11 is mounted on the mounting section to fix. By the constitution, the thickness of the outer case 13 can be thinned by setting the circuit plate 11 on the low tank side along the low tank 9, a hinge position of the toilet cover can be lowered, and a toilet room can make it look wider accordingly. Since it is not required to take any step to cope with the watering on the circuit substrate, costs can be reduced.