In an optical device, a first spring connects a first lens frame and a second lens frame for exerting a spring force thereon so that first pins of the first lens frame and second pins of the second lens frame abut a first cam groove and a second cam groove of a cam barrel respectively. A second spring connects the second lens frame and a third lens frame for exerting a spring force thereon so that the second pins of the second lens frame and third pins of the third lens frame abut the second cam groove and a third cam groove of the cam barrel respectively. The first spring may be a compression spring, and the second spring may be an extension spring.