A control method for a hot water supply system, the hot water supply system comprising: a heat pump hot water supplier; a hot water storage tank storing hot water heated by the heat pump hot water supplier; a heat exchanger using hot water stored in the hot water storage tank as a heat medium on a high temperature side; a hot water outflow pipe allowing communication between the heat pump hot water supplier and the hot water storage tank; a water inflow pipe allowing communication between the heat pump hot water supplier and the hot water storage tank; a hot water storage tank hot water outflow pipe allowing communication between the hot water storage tank and the heat exchanger; a hot water storage tank water inflow pipe allowing communication between the hot water storage tank and the heat exchanger; an on-site water inflow pipe communicating with the heat exchanger; an on-site hot water outflow pipe communicating with the heat exchanger; a hot water storage tank water inflow-side flow rate sensor installed in the hot water storage tank water inflow pipe; an on-site water inflow-side flow rate sensor installed in the on-site water inflow pipe; a hot water storage tank water inflow pipe temperature sensor installed in the hot water storage tank water inflow pipe; an on-site water inflow pipe temperature sensor installed in the on-site water inflow pipe; and a circulation pump, wherein the hot water supply system comprises a controller, and the controller receives values detected by the hot water storage tank water inflow-side flow rate sensor and the on-site water inflow-side flow rate sensor, wherein the controller generates an analog signal for controlling the circulation pump so that the value of the hot water storage tank water inflow-side flow rate sensor becomes equal to the value of the on-site water inflow-side flow rate sensor, and transmits the generated analog signal to the circulation pump, after the value of the hot water storage tank water inflow-side flow rate sensor becomes equal to the value of the on-site water inflow-side flow rate sensor, the controller receives temperatures detected by the hot water storage tank water inflow pipe temperature sensor and the on-site water inflow pipe temperature sensor, generates an analog signal for controlling the circulation pump so that the temperature of the hot water storage tank water inflow pipe temperature sensor becomes equal to the temperature of the on-site water inflow pipe temperature sensor, transmits the generated analog signal to the circulation pump, and controls output of the circulation pump. a heat pump hot water supplier; a hot water storage tank storing hot water heated by the heat pump hot water supplier; a heat exchanger using hot water stored in the hot water storage tank as a heat medium on a high temperature side; a hot water outflow pipe allowing communication between the heat pump hot water supplier and the hot water storage tank; a water inflow pipe allowing communication between the heat pump hot water supplier and the hot water storage tank; a hot water storage tank hot water outflow pipe allowing communication between the hot water storage tank and the heat exchanger; a hot water storage tank water inflow pipe allowing communication between the hot water storage tank and the heat exchanger; an on-site water inflow pipe communicating with the heat exchanger; an on-site hot water outflow pipe communicating with the heat exchanger; a hot water storage tank water inflow-side flow rate sensor installed in the hot water storage tank water inflow pipe; an on-site water inflow-side flow rate sensor installed in the on-site water inflow pipe; a hot water storage tank water inflow pipe temperature sensor installed in the hot water storage tank water inflow pipe; an on-site water inflow pipe temperature sensor installed in the on-site water inflow pipe; and a circulation pump, wherein the hot water supply system comprises a controller, and the controller receives values detected by the hot water storage tank water inflow-side flow rate sensor and the on-site water inflow-side flow rate sensor, wherein the controller generates an analog signal for controlling the circulation pump so that the value of the hot water storage tank water inflow-side flow rate sensor becomes equal to the value of the on-site water inflow-side flow rate sensor, and transmits the generated analog signal to the circulation pump, after the value of the hot water storage tank water inflow-side flow rate sensor becomes equal to the value of the on-site water inflow-side flow rate sensor, the controller receives temperatures detected by the hot water storage tank water inflow pipe temperature sensor and the on-site water inflow pipe temperature sensor, generates an analog signal for controlling the circulation pump so that the temperature of the hot water storage tank water inflow pipe temperature sensor becomes equal to the temperature of the on-site water inflow pipe temperature sensor, transmits the generated analog signal to the circulation pump, and controls output of the circulation pump.