1. An ophthalmologic apparatus that measures a movement of an eye to be inspected, the apparatus comprising: an image acquiring unit configured to acquire a plurality of fundus images of the eye to be inspected, at different times; a determining unit configured to determine a partial region based on a range of an eye movement and at least one of the plurality of the fundus images; a processing unit configured to perform processing, the processing being at least one of extraction and search of at least one characteristic image from the partial region; and a measuring unit configured to measure the movement of the eye by using the at least one characteristic image.