Electronic endoscope system

An electronic endoscope system comprising

• a light source device for sequentially emitting a plurality of light having different wavelength bands,
• an electronic endoscope for receiving reflected light of light emitted from the light source device and sequentially illuminating a subject tissue containing a blood vessel inside a body cavity and sequentially outputting an imaging signal corresponding to a wavelength band of the received light,
• an alignment means for aligning images corresponding to imaging signals of light having different wavelength bands outputted from the electronic endoscope,
• an image production means for producing an oxygen saturation level image representing a distribution of an oxygen saturation level in a blood vessel in a given depth from imaging signals of images aligned by the alignment means, and
• an image displaying means for displaying an oxygen saturation level image produced by the image producing means.