Abstract: An electronic endoscope that can automatically adjust the electronic characteristics of the processing amplifiers such as white balance, gamma balance, black level, or the like at optimum reference values. This is accomplished by selecting one of the plurality of the test-pattern charts so that the selected test-pattern chart, which represents one or more charateristics of the processing amplifiers to be adjusted, faces the tip of the probe of the endoscope, and by automatically setting control values of the video processing amplifiers in accordance with the selected chart by an auto-setup circuit so that the control values of the processing amplifiers agree with the reference values. Even technicians or doctors unfamiliar with operation of video processors can easily and accurately adjust color or the like of the endoscope.