PROBLEM TO BE SOLVED: To provide a method for evaluating the ratio of free unsaturated fatty acid in the sebum of a skin surface. SOLUTION: As for a plurality of spare subjects, the specified site of each cheek is irradiated with near ultraviolet rays from an irradiation part 12 and the surface of the skin containing the portion emitting the fluorescence is photographed by an image acquisition part 14 to acquire the image data. On the other hand, as for the skin surface specimens sampled, the data of the free unsaturated fatty acid in the sebum of the skin surface are obtained corresponding to each image by gas chromatography and both data are processed at an analysis part 18 to record the data that correspond to each other into a recording part 16. Then, the images for the subjects to be evaluated are obtained to evaluate the ratios of the free unsaturated fatty acid in the sebum of the skin surfaces of the subjects based on the correspondence-oriented information as recorded in the recording part 16. COPYRIGHT: (C)2004,JPO
