An optical apparatus according to the present invention enables a reduced drive distance in focusing operation of a focus lens to allow focus detection and focusing operation in a short time period. The optical apparatus has a detection unit which detects the attitude of the optical apparatus; and a controller which performs focus control for driving a focus lens included in an image-taking optical system based on a focus state of the image-taking optical system. The controller changes a drive start position of the focus lens in accordance with the attitude of the optical apparatus before the focus state of the image-taking optical system starts to be taken.