Abstract: In an embodiment, cross sectional image storage stores a cross sectional image group including multiple cross sectional images each of which is associated with time. Phase image storage stores a phase image group including multiple phase images each of which is associated with time. Blood flow information storage stores a blood flow information group including multiple blood flow information each of which is related to blood flow in a blood vessel of the living body and is associated with time. Display synchronously displays a cross sectional image included in the cross sectional image group and a phase image included in the phase image group using time associated with the cross sectional image and the phase image, and displays a blood flow image. The display performs the same change as the change to the change operation to the cross sectional image, the phase image and the blood flow image.