To provide a heat accumulation control device capable of suppressing reduction of nitrate that constitutes a heat accumulation material, and maintaining the heat accumulation performance.

The heat accumulation control device 11 comprises a case 12, a heat accumulation material 13 filled in the case 12, a heater 15 to heat the heat accumulation material 13, a thermocouple 16 which is disposed in the case 12 to detect the temperature of the heat accumulation material 13, and a heat transfer pipe 14 to transfer the heat of the heat accumulation material 13 to an inner heating medium. A temperature detection unit 17 provided on a tip of the thermocouple 16 is disposed so as to be brought into contact with a heat generation unit 18 of the heater 15. A control means to turn off energization to the heater 15 when the thermocouple 16 detects that the surface temperature of the heat generation unit 18 of the heater 15 reaches the predetermined heat accumulation temperature is provided. By turning off the heater 15 based on the surface temperature of the heater 15 reaching the highest temperature, overheat of nitrate 13a around the heater 15 is suppressed.