An optical instrument comprises a control section for driving a lens group in an optical axis direction, a first position detection section for detecting an absolute position of the lens group, a second position detection section for detecting a relative position of the lens group, and a storage section for storing first data corresponding to output of the second position detection section corresponding to a specified position, and second data corresponding to a target position, wherein, the control section acquires output of the second position detection section, at a point when a specified variation has occurred, as third data, calculates a stop target position based on the first data and the third data and executes a stop operation for the lens group to stop the lens group, and corrects output of the second position detection section in a state, based on the second data, and the stop target position.