WATER HEATER

PROBLEM TO BE SOLVED: To provide a water heater to rapidly restart supply of hot water after supply of hot water is stopped. SOLUTION: A discharge passage 10 branched from a hot water supply passage 1 is arranged in a spot situated upper stream from a thermo-sensitive actuating valve 8. Further, a discharge valve 9 is provided to open and close when the heat-sensitive actuating valve 8 is closed and opened, and open and close a discharge passage 10. When hot water having temperature higher then a given temperature flows out, the thermo-sensitive actuating valve 8 is closed, the discharge valve 9 is opened. This constitution causes a flow of hot water, having temperature higher than a given temperature, to the discharge passage 10 and a flow of hot water or water having temperature lower than the given temperature from a spot situated upper stream of a hot water passage 1, to the heat-sensitive actuating valve. When hot water or water having temperature lower that the given temperature flows, the thermo-sensitive actuating valve 8 is opened and the discharge valve 9 is closed. This constitution rapidly restarts supply of hot water after a stop of supply of hot water even when supply of hot water is stopped.