A fundus oculi observing device 1 specifies a characteristic site of a fundus oculi Ef depicted in tomographic images of the fundus oculi Ef and, based on the position of the characteristic site within frames FH and FV of the tomographic images, changes a target position of a signal light LS so that the characteristic site is depicted in the center positions within the frames FH and FV and executes a main measurement, thereby forming a tomographic image and/or a three-dimensional image of the fundus oculi Ef.