PURPOSE: To adjust room temperature in a short time in an air conditioner which controls air flow by bypassing a blower motor control means and directly supplying battery power when the room temperature exceeds a preset value or is lower the values than the other preset values.

CONSTITUTION: When the temperature of a car room is high, the resistance RS of a room temperature sensor 9 becomes smaller than a set point RO and the output of a comparator 21a is set to H and turns on transistor 21b and a relay contact 20b. The output is directly supplied to a fan motor from a battery power source 16 and bypasses a control amplifier 10. When the room temperature is cooled, the resistance RS is increased and the output of the comparator 21a is set to L. Accordingly, the transistor 21b is turned off, releases a relay 20, and turns off the bypass circuit of the control amplifier 10. As a result, when the room temperature exceeds a preset value or is lower than other preset values, battery voltage is directly applied and air flow can be increased.