PROBLEM TO BE SOLVED: To enhance fast-acting property at starting of cooling in an air conditioner using a brine. SOLUTION: A brine circuit 40 circulated with the brine cooled by a brine-coolant heat exchanger 7 is provided with first and second flow passages 41, 42 arranged in parallel at an exit side of the cooling heat exchanger 31 of an occupant seat 30, and the first flow passage 41 of them is arranged at the inside of a door D. When the seat becoming a high temperature by sunshine at parking in summer is cooled, the brine maintained to a low temperature is firstly flowed by a flow passage switching mechanism 43 using the first flow passage 41, and thereafter, when the brine of high temperature flowing from the inside of the seat is accumulated in the first flow passage 41, it is switched to the second flow passage 42 to circulate the brine becoming the high temperature to the brine circuit 40. COPYRIGHT: (C)2008,JPO&INPIT