An endoscope apparatus includes an excitation-light radiation unit; a fluorescence-image acquisition unit; a fluorescence-spectrum storage unit; a density computation unit, an image combining portion; and an image display portion; wherein when coefficients at wavelengths of fluorescent components obtained from the fluorescence spectra in the storage unit, and when intensities of fluorescence images at the wavelengths acquired by the acquisition unit, the density computation unit calculates the densities of the fluorescent components from an equation, and when the densities are calculated, in accordance with a change in the value of an exposure condition item during acquisition of the fluorescence image at a wavelength, the density computation unit changes the coefficients at the wavelength using the ratio of the value after the change to the value of the exposure condition items under the reference exposure conditions has been made.