A diagnosis support apparatus, includes a spatial structure data acquisition device that acquires spatial structure data including tomographic information of a three-dimensional region of an inner wall portion within a living organism that has a flat surface at a normal time that is obtained by performing optical coherence tomography measurement with respect to the inner wall portion； a surface roughness calculation device that calculates an evaluation value of a surface roughness at respective positions on the surface of the inner wall portion based on the spatial structure data； a lesion part extraction device that extracts a region of a lesion part based on a position on the surface at which the evaluation value exceeds a predetermined threshold value； and a lesion part display device that displays information showing the region of the lesion part on an image in which the spatial structure data is visualized.
