To provide an instantaneous heating of a toilet seat for achieving quick heating and a clean toilet seat.

A lamp heater 2 installed inside the toilet seat is controlled by a triac 5 by using signals from a human body detection sensor 10, a thermistor 3, a seating sensor 4, and a zero crossing detection circuit 6. The human body sensor 10 senses that there is no user, and the lamp heater 2 is rapidly heated by the triac 5 so that the toilet seat 1 is set to a temperature 10-20°C higher than a temperature at the time of normal use for performing high-temperature sterilization of the toilet seat 1. While the high-temperature sterilization is performed, a toilet cover 12 is closed so as to prevent the user from sitting on the toilet seat 1 during the high-temperature sterilization.