To provide a structure which can ensure a retaining force of an optical control member such as a vane member and which is suited to size reduction and compactness, in applying the optical control member to a drive device.

A magnetic-mechanical conversion element 3 capable of obtaining huge magnetic strain with a Joule effect is used in driving an iris or a shutter, so as to convert a driving force caused by an expansion change in the element corresponding to a magnetic field change, into a rotational force or a moving force of the vane member. Accordingly, higher vane retaining force can be obtained under the same applied voltage than a conventional electrostrictive element or magnetostrictive element, thus attaining high-speed driving.