VEHICULAR AIR CONDITIONER

PROBLEM TO BE SOLVED: To provide a motor-driven compressor without arranging an exclusive motor, and to freely adjust a load of the compressor without increasing a cost and weight by using an engine starting starter motor for driving the compressor except for engine starting time. SOLUTION: A temperature of refrigerant gas in an air conditioner is lowered by a heat cycle for refluxing a refrigerant in order of a compressor 3, a capacitor 31, a receiver tank 32, an expansion valve 33 and an evaporator 5. In this case, a controller 9 connects an electromagnetic clutch CL by a clutch signal (a) on condition that the connection of a starter motor 2 and an engine 1 is released after starting the engine. When a driver turns on an air conditioner switch, the controller 9 actuates the starter motor 2 by outputting an electric power control signal (b) to drive the compressor 3 at an optimal rotating speed according to a temperature set by the driver, an outside air temperature and a room temperature.