A heat pump system (1, 200, 300, 400), comprising: a heat source unit having a compressor adapted to compress a refrigerant, and a heat-source-side heat exchanger, characterized by a heat-source-side switching mechanism adapted to switch between a radiating operation state in which the heat-source-side heat exchanger is made to function as a radiator of refrigerant and an evaporating operation state in which the heat-source-side heat exchanger is made to function as an evaporator of refrigerant; a first usage unit adapted to perform a hot-water supply operation for heating an aqueous medium by the heat radiation of the refrigerant in a first usage-side heat exchanger, the first usage unit being connected to the heat source unit and having the first usage-side heat exchanger adapted to function as a radiator of refrigerant when the heat-source-side switching mechanism is in the evaporating operation state and a first usage-side controller for issuing commands to the first usage unit; and a second usage unit (10a, 10b) adapted to perform an air-cooling operation for cooling an air medium by the evaporation of the refrigerant in a second usage-side heat exchanger (101a, 101b), and adapted to perform an air-warming operation for heating the air medium by the heat radiation of the refrigerant in the second usage-side heat exchanger (101a, 101b), the second usage unit (10a, 10b) being connected to the heat source unit and having the second usage-side heat exchanger (101a, 101b) adapted to function as an evaporator of refrigerant when the heat-source-side switching mechanism is in the radiating operation state and adapted to function as a radiator of refrigerant when the heat-source-side switching mechanism is in the evaporating operation state and a second usage-side controller (108a, 108b) for issuing commands to the second usage unit (10a, 10b); a centralized controller for issuing shared control setting and operation commands shared by the entire heat pump system (1, 200, 300, 400); wherein the first usage unit and the second usage unit (410a, 10b) are incapable of individually selecting and operating the hot-water supply operation, the air-cooling operation, or the air warming operation, and the heat pump system (1, 200, 300, 400) is adapted to switch to and to operate in a thermoregulation mode different from the switched state of the heat-source-side switching mechanism as the thermoregulation mode issued by command of the first usage-side controller for issuing commands to the first usage unit, the second usage-side controller (108a, 108b) for issuing commands to the second usage unit (10a, 10b), or the centralized controller that is separate from the first usage-side controller and the second usage-side controller (108a, 108b). a heat source unit having a compressor adapted to compress a refrigerant, and a heat-source-side heat exchanger, characterized by a heat-source-side switching mechanism adapted to switch between a radiating operation state in which the heat-source-side heat exchanger is made to function as a radiator of refrigerant and an evaporating operation state in which the heat-source-side heat exchanger is made to function as an evaporator of refrigerant; a first usage unit adapted to perform a hot-water supply operation for heating an aqueous medium by the heat radiation of the refrigerant in a first usage-side heat exchanger, the first usage unit being connected to the heat source unit and having the first usage-side heat exchanger adapted to function as a radiator of refrigerant when the heat-source-side switching mechanism is in the evaporating operation state and a first usage-side controller for issuing commands to the first usage unit; and a second usage unit (10a, 10b) adapted to perform an air-cooling operation for cooling an air medium by the evaporation of the refrigerant in a second usage-side heat exchanger (101a, 101b), and adapted to perform an air-warming operation for heating the air medium by the heat radiation of the refrigerant in the second usage-side heat exchanger (101a, 101b), the second usage unit (10a, 10b) being connected to the heat source unit and having the second usage-side heat exchanger (101a, 101b) adapted to function as an evaporator of refrigerant when the heat-source-side switching mechanism is in the radiating operation state and adapted to function as a radiator of refrigerant when the heat-source-side switching mechanism is in the evaporating operation state and a second usage-side controller (108a, 108b) for issuing commands to the second usage unit (10a, 10b); a centralized controller for issuing shared control setting and operation commands shared by the entire heat pump system (1, 200, 300, 400); wherein the first usage unit and the second usage unit (410a, 10b) are incapable of individually selecting and operating the hot-water supply operation, the air-cooling operation, or the air warming operation, and the heat pump system (1, 200, 300, 400) is adapted to switch to and to operate in a thermoregulation mode different from the switched state of the heat-source-side switching mechanism as the thermoregulation mode issued by command of the first usage-side controller for issuing commands to the first usage unit, the second usage-side controller (108a, 108b) for issuing commands to the second usage unit (10a, 10b), or the centralized controller that is separate from the first usage-side controller and the second usage-side controller (108a, 108b).