An optical instrument of the present invention comprises a ring member which is arranged to be rotatable with respect to a lens barrel, and also to slide in an optical axis direction to a first position and a second position, a rotation position detection section for outputting a preset distance that has been set by a rotation operation, when the ring member is at the second position, and a control section for, when the ring member has been subjected to a slide operation between the first position and the second position, moving a photographing lens at a first speed or a second speed up to a distance corresponding to an operation position.