To decrease heating amount of a heater by warming a washing tank as much as possible with the aid of heat radiated by a rinsing tank.

It has a washing room 2 which washes tableware, a washing tank 4 which supplies washing water to the washing room 2, located under the washing room 2, a washing water heater 29 installed in the washing tank 4 which keeps warmth of washing water stored in the washing tank 4 in a fixed degree, a rinsing tank 5 which stores and keeps rinsing water warmer than washing water in order to rinse tableware in the washing room 2, located under the washing tank 4, and a rinsing water heater 32 which heats rinsing water, installed in the rinsing tank 5.