PURPOSE: To provide a heat supply device in which a total running cost can be lowered by forming the optimum operation plan of heat pumps with a control equipment, which is provided with a heat demand predicting function, for operating all the heat pumps at their maximum efficiency points, enabling the energy- saving operations of the heat pumps and shortening the operating time during daytime.

CONSTITUTION: A heat supply device is provided with a plurality of heat pumps 11 to 15 and a hot-water/cold water heat storage tank 19 and controls their operations so that the quantity of heat stored in the heat storage tank 19 by the regenerative operation of the heat pumps 11 to 15 at night is completely consumed in a prescribed time zone (8 o'clock a.m. to 10 o'clock p.m.) during daytimne. A control part 17 is provided, for operating all the heat pumps at their maximum efficency points based on the output of a heat storage quantity detector 18 for detecting the quantity of heat storage in the heat storage tank 19 and a predicted quantity of heat demand in the prescribed time zone during daytime and for controlling to start the heat pumps 80 that the number of startings of the heat pumps is minimum without exceeding the upper limit and lower limit of the quantity of heat storage of the heat storage tank 19.