Abstract: In an opening/closing member driving method in which the rotation of a motor rotatable in two directions is transmitted through a transmission member to an opening/closing member to thereby drive a baffle 4 in an opening direction A and in a closing direction B, when driving the transmission member from an intermediate position to an original position which is set at a position where the transmission member is moved to the full in one direction or in the other direction, the transmission member is once driven in the opposite direction to the original position and is stopped at such opposite position or in the neighborhood of the opposite position and, after then, the transmission member is driven in the original position direction by an amount equivalent to the normal movement thereof and is thereby returned to the original position.