To relax water hammering in a bath heat exchanger upon starting hot water supply.

A storage type bath hot water supply device includes: a bath heat exchanger 14 disposed in a hot water storage tank 1 for heating bathtub water; a heat exchange bypass pipe 19 connecting a bath returning pipe 17 and a bath going pipe 16 while bypassing the bath heat exchanger 14; a hot water supply circuit 29 connected on the way at a bathtub 13 side with respect to a confluent point to the heat exchange bypass pipe 19, of the bath returning pipe 17, and supplying hot water to a bathtub 13; an opening/closing valve 27 disposed in the hot water supply circuit 29; and a bath flow channel switch valve 20 disposed on the confluent point to the heat exchange bypass pipe 19, of the bath returning pipe 17 and switching between a flow of the hot water from the bath returning pipe 17 to a bath heat exchanger 14 side and a flow to a heat exchange bypass pipe 19 side. Upon starting the hot water supply, the heat exchange bypass pipe 19 side is half-opened while closing the bath heat exchanger 14 side of the bath flow channel switch valve 20, and then the hot water supply opening/closing valve 27 is opened to start hot water supply.