1. A transparency evaluation device comprising: an image input processor that inputs a captured image obtained by photographing a skin of a subject; a skin index calculation processor that calculates at least one of a representative value of a luminance component in the captured image, a representative value of a color component in the captured image, and an amount of generation of negative factors in which a value of the luminance component or a value of the color component in the captured image changes locally, as a first skin evaluation index, obtains at least one of an intensity distribution of the luminance component and an intensity distribution of the color component in the captured image, and calculates at least one of smoothness of a change in the luminance component and smoothness of a change in the color component as a second skin evaluation index based on the obtained intensity distributions; an overall index calculation processor that combines a plurality of evaluation indexes including the first skin evaluation index and the second skin evaluation index calculated by the skin index calculation processor with one another to calculate an overall index for transparency of the skin; and a transparency evaluation processor that evaluates transparency of the skin of the subject based on the overall index calculated by the overall index calculation processor.