An endoscope observation method includes irradiating first and second narrowband light to an observation object. The first and second narrowband light have wavelengths at which absorbances of first and second characteristic substances related to a predetermined state of the observation object and contained in the observation object are mutually different. The method also includes performing imaging by use of reflected light of the first and second narrowband light from the observation object to obtain first and second image data, and forming a characteristic substance presence image regarding the presence of the first and second characteristic substance, on the basis of characteristic amounts of the first and second characteristic substances contained in the first and second image data.