A diagnosis apparatus in which a lesion in the large intestine can be
diagnosed with high precision by detecting pits is provided. A
three-dimensional optical tomographic image is obtained by the
configuration of an apparatus using an endoscope and an optical probe,
images in X-Y planes perpendicular to the depth direction of a living
body tissue are cut out at a plurality of depth positions, based on the
three-dimensional tomographic image data, and a pit pattern shape
highlighted image is generated from their average image to perform
diagnostic support.