PURPOSE: To provide an efficient hot water supply device for bath by preventing the penetration of air into an additional heating circuit from an air release opening of a hopper, inhibiting the cooling of hot water in a bath tub and reducing air eliminating operation of the additional heating circuit during an automatic intermittent hot water filling operation into the bath tub located below a hopper valve.

CONSTITUTION: There is installed an automatic hot water supply on/off valve A 10 which controls the supply of hot water into a bath tub 19 from a hot water supply heater 33 and feeds hot water into a hopper 12. An automatic hot water supply on/off valve B 45 which on/off controls the bath tub 19 and an inlet line 17 and a three way changeover valve 46 where differential time ΔT is provided by means of a control valve 26 which controls the automatic hot water supply on/off valves A and B and the three way changeover valve 46 so that the valves may be on/off controlled for every operation mode are also installed. The action of negative pressure produced when the bath tub is lower than a hopper valve 24 prevents the intake of air from an air release opening 40 of the hopper 12.