An image processing device includes: a spectral reflectance calculation unit that calculates a spectral reflectance on the basis of intensities of reflection light and irradiation intensities; a color value calculation unit that obtains color values based on the spectral reflectance; a coefficient calculation unit that calculates coefficients respectively for a plurality of predetermined eigenvectors where the color values are expressed by a linear combination between the plurality of predetermined eigenvectors, the coefficients, and spectral energies of at least two types of irradiation light; and an output unit that generates and outputs information corresponding to estimation values within a wavelength range defined by excluding at least one of a low and a high wavelength ranges from the wavelength range including the wavelengths of visible light, among estimation values of the spectral reflectances expressed by linear combination between the respective coefficients calculated by the coefficient calculation unit and the eigenvectors.