Abstract: In an air passage switching device, suitable for use for example in a vehicle air conditioning apparatus, for switching a flow of air among a plurality of air passages by moving a film door in one direction by a stepping motor and in another direction by the spring force of coil spring, when the film door is moved in the direction in which it winds up the coil spring the pulse rate of the stepping motor is reduced to thereby increase the motor torque and prevent the occurrence of a shortage of motor torque. When the film door is moved in the other direction the pulse rate of the stepping motor is increased to reduce the motor torque.