A heating and hot water supply system comprising: heating means for heating a heat medium; a hot water supply heat exchanger that performs heat exchange between the heat medium and water; a hot water storage tank that stores water heated by the hot water supply heat exchanger; a heating heat exchanger that heats an inside of a room using the heat medium; a heat medium pump that feeds the heat medium; a circulation pipe that annularly connects a discharge side of the heat medium pump, the heating means, the hot water supply heat exchanger, the heating heat exchanger, and a suction side of the heat medium pump in order; a first bypass pipe that bypasses the hot water supply heat exchanger from the circulation pipe; a second bypass pipe that bypasses the heating heat exchanger from the circulation pipe; first flow regulating means that is provided at a junction between the circulation pipe and the first bypass pipe, and regulates a ratio between a flow rate of the heat medium flowing into the hot water supply heat exchanger and a flow rate of the heat medium flowing into the first bypass pipe; a second flow regulating means that is provided at a junction between the circulation pipe and the second bypass pipe, and regulates a ratio between a flow rate of the heat medium flowing into the heating heat exchanger and a flow rate of the heat medium flowing into the second bypass pipe; and control means for controlling the first flow regulating means and the second flow regulating means in accordance with degrees of a hot water supply request for heat exchange by the hot water supply heat exchanger and a heating request for heat exchange by the heating heat exchanger. heating means for heating a heat medium; a hot water supply heat exchanger that performs heat exchange between the heat medium and water; a hot water storage tank that stores water heated by the hot water supply heat exchanger; a heating heat exchanger that heats an inside of a room using the heat medium; a heat medium pump that feeds the heat medium; a circulation pipe that annularly connects a discharge side of the heat medium pump, the heating means, the hot water supply heat exchanger, the heating heat exchanger, and a suction side of the heat medium pump in order; a first bypass pipe that bypasses the hot water supply heat exchanger from the circulation pipe; a second bypass pipe that bypasses the heating heat exchanger from the circulation pipe; first flow regulating means that is provided at a junction between the circulation pipe and the first bypass pipe, and regulates a ratio between a flow rate of the heat medium flowing into the hot water supply heat exchanger and a flow rate of the heat medium flowing into the first bypass pipe; a second flow regulating means that is provided at a junction between the circulation pipe and the second bypass pipe, and regulates a ratio between a flow rate of the heat medium flowing into the heating heat exchanger and a flow rate of the heat medium flowing into the second bypass pipe; and control means for controlling the first flow regulating means and the second flow regulating means in accordance with degrees of a hot water supply request for heat exchange by the hot water supply heat exchanger and a heating request for heat exchange by the heating heat exchanger.