A temperature control system includes a heater core utilizing heat of a heat medium; an engine heat exchanger utilizing exhaust heat of an engine to heat the heat medium; a condenser utilizing heat other than the exhaust heat to heat the heat medium; a heat circuit having the heater core and condenser; a communication flow path making the engine heat exchanger communicate with the heat circuit; and a connection state switching mechanism switching a flow state of the heat medium, between a first state and a second state. In the first state, the heat medium flows through the heat circuit, while flowing through the heater core, and in the second state, the heat medium flows through the heat circuit without flowing through the heater core. The heat circuit is arranged at a front of a passenger compartment, and the engine heat exchanger is arranged at a rear of the compartment.