A device is an OCT device that splits a low-coherence light into a signal light and a reference light, detects an interference light obtained by superimposing the signal light propagated through an eye and the reference light propagated through a reference mirror, and forms an image of an fundus oculi. The device has a scan unit that scans the eye with the signal light. When a cross-section position is designated in an fundus oculi image, the device repetitively scans with the signal light along each cross-section position to repeatedly forms tomographic images at each cross-section position, thereby displaying a tomographic motion image at each cross-section position on a display. An operator can observe the tomographic motion image to designate the range and timing for measurement of a tomographic still image.
