If an image sensing lens is retracted into a camera body when the voltage of the camera battery is low, the battery voltage will fall below a prescribed value. The lens retracting operation, therefore, is brought to a rapid halt in such case. Owing to the rapid halt, the battery voltage rises above the prescribed value. The retraction of the lens is then performed slowly. The slowed retraction of the lens makes it possible to prevent the battery voltage from falling too suddenly. Since the battery voltage will not drop even through the retracting operation is resumed, it is possible to prevent the retracting operation from being rapidly halted again owing to a drop in battery voltage.