An object is to allow grasp of a depth position of a corneal image. A cornea observation device 100 functions as a full-field OCT device and forms a horizontal tomographic image of a cell of a cornea Ec. A cellular-region extracting part 243 extracts a cellular image region from this tomographic image. A cellular-information generator 244 generates cellular information representing a cellular morphology (size and shape) based on this image region. A memory 247 pre-stores relation information 247a relating a depth position of the cornea to the cellular morphology. A depth-position specifying part 245 selects a depth position corresponding to the cellular morphology of the cornea Ec shown in the cellular information from the relation information 247a and sets as the depth position of the tomographic image. A controller 21 makes a display 22 display this depth position. Consequently, an operator can grasp the depth position of the tomographic image.
