An endoscope apparatus comprises: an endoscope comprising an imaging device that forms a color image signal of a body to be observed a storage portion that stores matrix data regarding a wavelength range in which a spectral image is constituted a spectral image forming circuit that conducts matrix calculation based on the color image signals by using the matrix data of the storage portion and forms a spectral image of a selected wavelength range and a wavelength selecting section that selects the wavelength range of the spectral image formed by the spectral image forming circuit through a continuous changeover or a step-wise changeover.
