The invention discloses a simple auxiliary tube device for endoscopic treatment. The simple auxiliary tube device for endoscopic treatment comprises a short hard tube, a ductile main tube, an elongated hard tube and traction strings, wherein the short hard tube is fixed on a lateral endoscope body in the bent direction of the front end of an endoscope body, and the front end of the short hard tube is flush with the front end of the endoscope body; the main tube is fixed on the lateral endoscope body in the bent direction of the front end of the endoscope body, is positioned on the same side as the short hard tube and clings to the short hard tube, the front end of the main tube is flush with the front end of the endoscope body, and a tube section in the front of the main tube is detachably arranged on the endoscope body; the elongated hard tube is fixed to the endoscope body closely to the main tube and is arranged on the side as the short hard tube; one end of one traction string is tied to the head end of an auxiliary treatment accessory while the other end thereof is positioned outside the endoscope body; one end of each of the other two traction strings is tied to the head end of the main tube and passes through holes of the short hard tube and two independent holes of the elongated hard tube. The simple auxiliary tube device for endoscopic treatment is capable of achieving 'two-arm' operation and aiding endoscopic treatment flexibly and rapidly.