An image processing device includes: an absorbance calculating unit configured to calculate absorbances at wavelengths based on pixel values of a plurality of pixels constituting an image； a component amount estimating unit configured to estimate amounts of two or more kinds of light absorbing components contained respectively in two or more kinds of tissue including specified tissue by using an absorbance in a first wavelength band among the absorbances at the wavelengths calculated by the absorbance calculating unit, the first wavelength band being a part of the wavelengths； an estimation error calculating unit configured to calculate estimation errors caused by the component amount estimating unit； and a depth estimating unit configured to estimate a depth at which the specified tissue is present in the object based on an estimation error in a second wavelength band with shorter wavelength than the first wavelength band among the estimation errors.
