Abstract: A temperature control system for a vehicle includes a refrigeration cycle circuit and a cooling water circuit. The refrigeration cycle circuit includes a compressor, a radiator, and a first heat exchanger that exchanges heat between refrigerant and cooling water. The cooling water circuit includes a first cooling water circuit including the first heat exchanger, a storage battery heat exchanger, and a first pump; a second cooling water circuit including an external heat exchanger, a drive system heat exchanger that exchanges heat with a drive system component, and a second pump; a first thermal coupler that switches the cooling water circulating through the first cooling water circuit and the cooling water circulating through the second cooling water circuit between thermal coupling and separation; and a bypass circuit that includes an on-off valve connected to upstream and downstream of the external heat exchanger, provided in parallel with the first cooling water circuit.