A processor for an electronic endoscope, which is configured to be connected with a videoscope adapted to generate a picture signal for an image of an observed object through color adjustment using color adjustment data and to transmit the generated picture signal to the processor, the processor includes a light source configured to emit light for illuminating the observed object, a determining unit configured to determine whether the color adjustment data used by the videoscope is adapted to the light source, a color conversion data acquiring unit configured to acquire color conversion data adapted to the color adjustment data when the determining unit determines that the color adjustment data is not adapted to the light source, and a color converter configured to perform color conversion for the picture signal transmitted by the videoscope using the color conversion data acquired by the color conversion data acquiring unit.