A profile is created on the basis of an interference signal obtained by optical coherence tomography, the profile having optical reflectance in relation to depth in a depth range that extends from the epidermis to the dermal upper layer. The difference between a reflectance (R1) at a minimum point (P1) and a reflectance (R2) at a maximum point (P2) is calculated from the created profile to obtain an evaluation index. The state of skin is evaluated on the basis of the evaluation index.
