An optical fat thickness meter includes a light source section which is provided on a measuring surface and which emits light to a living body, a photoreception section which is provided on the measuring surface, and which receives the light passing the living body, a protruding section which is provided so as to surround the light source section and photoreception section substantially, and an arithmetic section which calculates information with regard to a living body on the basis of the amount of the received light.