Patent ID: 7446796

Claim:
An electronic endoscope system comprising: an electronic endoscope having an insertion portion; an image pickup device provided at a distal end of said insertion portion; an image signal processing device for converting a signal picked-up by and output from the image pickup device into an image signal; a main light source; an auxiliary light source which emits less amount of light than the light emitted from the main light source, instead of the main light source; and a light guide member which guides illumination light emitted from one of the main light source and the auxiliary light source to the distal end of said insertion portion to thereby emit the illumination light from said distal end; wherein, when the auxiliary light source emits the illumination light instead of the main light source, said image signal processing device sets the gain of said signal output from the image pickup device to a value higher than the gain of said signal when the main light source emits the illumination light, in order to process the image signal.