Abstract: An electronic endoscope system equipped with a suction channel, capable of freely adusting the inhalation strength of the suction channel. The system includes a suction switch to be pressed by an operator for indicating a desired strength of inhalation through th esuction channel by an extent of depression; a sensor for dtecting the extend of depression of the suction switch; a pinching valve for adjusting a strength of inhalation through the suction channel by adjustably changing an extend of opening; and a controlling unit for controlling the strength of inhalation through the suction channel to the desired strength of inhalation through the suction channel indicated by the suction swtich, by adjusting the extend of opening of the pinching valve in accordance with the extent of depression of the suction switch detected by the sensor.