A diaphragm switching apparatus according to the present invention comprises a gear adapted to rotate in response to a driving force of a focus motor used for driving a focus lens; a shaft for rotatably supporting the gear; a diaphragm switching means, secured to the shaft 12 and adapted to rotate together with the shaft, for switching a diaphragm upon rotating; an intermediate member engaging the diaphragm switching means so as to rotate together with the shaft and being slidable axially with respect to the shaft; an urging means for urging the gear away from the diaphragm switching means by way of the intermediate member by receiving a reaction force from the diaphragm switching means; and a holding part 12a for receiving the gear urged by the urging means.