A skin diagnosing device 1 includes an optical unit 2 including: an optical system that uses the OCT； an optical mechanism 4 to guide light from the optical unit 2 to skin S to scan the skin； a loading device 5 to apply predetermined deformation energy to the skin S； a control computation unit 6 to compute tomographic distribution of predetermined status values relating to the skin S by controlling driving of the loading device 5 and the optical mechanism 4 and processing optical interference signals output from the optical unit 2 in response to the driving, to compute an evaluation value of the skin S on the basis of the tomographic distribution； and a display device 74 to display the evaluation value of the skin S. The control computation unit 6 computes the evaluation value by computing mechanical characteristics and a blood flow condition of the skin S as the status values and associating the mechanical characteristics and the blood flow condition at a cross-sectional position of the skin S.
