A method for acquiring a tomographic image that is sufficiently used for diagnosing a target tissue or measuring an image by controlling the irradiation angle of a signal light beam on the retina at a predetermined position is provided.An image-capturing instruction unit 301 sends, to an image capturing unit 101, an instruction to emit a signal light beam to the retina at a first irradiation angle and capture the image of the retina. A tomographic image acquiring unit 302 acquires a tomographic image captured by the image capturing unit 101, and a shape analyzing unit 303 analyzes the layer structure of the retina and identifies at least part of the shape of a depressed part. If the shape is not identified, the shape is estimated using interpolation. A re-image capturing determination unit 304 determines whether re-image capturing is necessary on the basis of the presence of a partial area of the depressed part that cannot be identified or the size of the partial area. Using the shape of the depressed part obtained by the shape analyzing unit 303, a re-image capturing angle determination unit 305 determines a second irradiation angle at which an area in which the intensity of a returning light beam output from the depressed part is lower than a predetermined intensity is minimized. The image-capturing instruction unit 301 instructs re-image capturing on the basis of the determined irradiation angle.
