A structural area extracting unit (13a) extracts a structural area from one intraluminal image. A corresponding area extracting unit (13b) extracts a corresponding area corresponding to the structural area extracted from the one intraluminal image by the structural area extracting unit (13a) from another intraluminal image captured at time different from the time of capturing the one intraluminal image. A lumen deep portion extracting unit (13c) extracts a lumen deep portion located further in a moving direction of an imaging device (2) from the one intraluminal image. A movement amount estimating unit (13d) estimates a movement amount of the imaging device (2), which moves from time of capturing the one intraluminal image to time of capturing the another intraluminal image based on positional relationship between the structural area in the one intraluminal image, the corresponding area in the another intraluminal image and the lumen deep portion.
