An endoscope treatment system comprises plural types of treatment instruments, plural types of adapters, and an advancing and retracting device. The treatment instmments include treatment instrument inserting sections which can be inserted into a treatment instrument channel of an endoscope. The treatment instruments have different outer diameter dimensions depending on their types. The adapters are attached to the treatment instrument inserting sections having different outer diameter dimensions to form surface to be pressed which has a fixed dimension for the treatment instruments. The adapters respectively have a through-hole corresponding to each diameter dimension of the treatment instrument inserting sections. The advancing and retracting device includes a pair of rollers separated by a distance corresponding to the surface to be pressed of a fixed dimension. The rollers hold the surface to be pressed of the adapter attached to the treatment instrument inserting section under a predetermined pressure. A rotation of the rollers with the adapter being held between the rollers causes the adapter to advance and retract.
