PURPOSE: To achieve comfortable air-conditioning continuously by providing a bench mode switch between an air-conditioning control switch and relay thereby blowing the maximum air flow into the cabin upon exchanging to bench mode.

CONSTITUTION: A rotary contactor C5 of fan switch 5 is contacted with desired fixed contacts C1WC4 to vary the resistance of resistor 4 thus to rotate a fan motor 3 and to regulate the air flow. Upon exchange of an air-conditioning switch 6 from cooler mode to bench mode, a bench mode switch 9 will close to flow current through a coil 7a of relay 7 thus to close the contact 7b and to shortcircuit resistor R1 in resistor 4. Consequently, the air flow is increased by one step to improve ventilation. In such a manner, it can be selected to the maximum air flow in bench mode while to the optimal air flow when exchanged to heater mode or def. mode, resulting in comfortable air-conditioning at any time.