a high-temperature side heating medium circuit in which a heating unit heats a heating medium, a heater core that radiates heat of the heating medium to air blown to a space to be air-conditioned, and a first heating medium pump that pumps the heating medium are connected so that the heating medium is allowed to circulate therethrough;

a low-temperature side heating medium circuit in which a radiator that radiates heat of the heating medium to outside air, a heat generation device generates heat in accordance with an operation and whose temperature is adjusted by heat of the heating medium, and a second heating medium pump that pumps the heating medium are connected so that the heating medium is allowed to circulate therethrough;

a device heating medium circuit in which a device heat exchange unit exchanges heat between a target device to be subjected to temperature adjustment and the heating medium, the device heat exchange unit being connected so that the heating medium is allowed to flow in and out, and a third heating medium pump that pumps the heating medium are connected so that the heating medium is allowed to circulate therethrough;

a circuit connection portion that connects the high-temperature side heating medium circuit, the low-temperature side heating medium circuit, and the device heating medium circuit so that the heating medium is allowed to flow in and out; and

a circuit switch unit switches a flow of the heating medium in the high-temperature side heating medium circuit, the low-temperature side heating medium circuit, the device heating medium circuit, and the circuit connection portion, wherein

the circuit switch unit switches between

an operation mode in which the heating medium that passed through the low-temperature side heating medium circuit is circulated through any one of the high-temperature side heating medium circuit and the device heating medium circuit via the circuit connection portion and

an operation mode in which the high-temperature side heating medium circuit, the low-temperature side heating medium circuit, and the device heating medium circuit are connected via the circuit connection portion, and the heating medium is circulated through the heat generation device, the device heat exchange unit, the heating unit, and the heater core, and

a circulation path of the heating medium in the operation mode in which the high-temperature side heating medium circuit, the low-temperature side heating medium circuit, and the device heating medium circuit are connected via the circuit connection portion, and the heating medium is circulated through the heat generation device, the device heat exchange unit, the heating unit, and the heater core is configured so that any one of the first heating medium pump, the second heating medium pump, and the third heating medium pump is disengaged.