A shape estimation device includes an input circuit, a storage circuit and an arithmetic circuit. The input circuit receives light amount information being a relationship between a wavelength and a light amount. The light amount information is acquired by using a sensor configured such that the light amount to be detected with respect to the wavelength corresponding to each of sensing parts varies in accordance with a shape of each sensing part. The storage circuit stores a light amount estimation relationship including a relationship among the shape, the wavelength and the light amount. The arithmetic circuit calculates a light amount estimation value by an optimization arithmetic operation such that the estimation value based on the light amount estimation relationship and the light amount information satisfy a predetermined condition.
