An image displaying apparatus, comprising: a cross sectional image storage configured to store a cross sectional image group including multiple cross sectional images each of which is associated with time and expresses a cross section intersecting at least one blood vessel of a living body; a phase image storage configured to store a phase image group including multiple phase images each of which is associated with time and expresses chronological variation of phase difference at a cross section intersecting at least one blood vessel of the living body; a blood flow information storage configured to store 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, and a display configured to synchronously and superposedly display 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 display a blood flow image that expresses multiple blood flow information, from among blood flow information included in the blood flow information group, corresponding to time within a period including time associated with the cross sectional image and the phase image that are being superposedly displayed, characterized in that the apparatus is configured to perform position matching between cross sectional images and phase images acquired at the same location in the living body, and that the image displaying apparatus further comprises a change operation receiving part configured to receive a change operation for changing display of one of the superposed image of the cross sectional image and the phase image and the blood flow image that are displayed by the display, wherein the display is configured to perform the same change as the change corresponding to the change operation to the superposed image of the cross sectional image and the phase image and the blood flow image that are displayed by the display. a cross sectional image storage configured to store a cross sectional image group including multiple cross sectional images each of which is associated with time and expresses a cross section intersecting at least one blood vessel of a living body; a phase image storage configured to store a phase image group including multiple phase images each of which is associated with time and expresses chronological variation of phase difference at a cross section intersecting at least one blood vessel of the living body; a blood flow information storage configured to store 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, and a display configured to synchronously and superposedly display 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 display a blood flow image that expresses multiple blood flow information, from among blood flow information included in the blood flow information group, corresponding to time within a period including time associated with the cross sectional image and the phase image that are being superposedly displayed, characterized in that the apparatus is configured to perform position matching between cross sectional images and phase images acquired at the same location in the living body, and that the image displaying apparatus further comprises a change operation receiving part configured to receive a change operation for changing display of one of the superposed image of the cross sectional image and the phase image and the blood flow image that are displayed by the display, wherein the display is configured to perform the same change as the change corresponding to the change operation to the superposed image of the cross sectional image and the phase image and the blood flow image that are displayed by the display.