To provide a hot water storage type heating device capable of preventing freezing of a secondary circulation circuit without lowering a room temperature and generating dew condensation.

A heat medium temperature detecting means 28 for detecting a temperature of a heat medium flowing in the secondary circulation circuit 17 is disposed in the secondary circulation circuit 17, a switching means 22 is switched to a taking-out port 20 side when the temperature of the heat medium detected by the heat medium temperature detecting means 28 becomes lower than an antifreezing temperature, a primary-side circulation pump 10 is driven to circulate the hot water from a taking-out pipe 21 to a primary circulation circuit 12, the heat medium heated through a heating heat exchanger 4 is circulated in the secondary circulation circuit 17 by driving a secondary-side circulation pump 18 disposed in the secondary circulation circuit 17, thus the freezing of the secondary circulation circuit 17 can be prevented, the lowering of a room temperature and generation of dew condensation can be prevented, and initial starting load in using floor heating can be reduced with preheating action by the circulation of the heated heat medium.