Abstract: An overtube device and an endoscope assembly are provided, the overtube device includes an overtube body having a proximal end and a distal end, the overtube body is provided with a bore which extending from the distal end to the proximal end of the overtube body, the bore is configured to allow a passing portion of the endoscope assembly to pass therethrough; a pulling lumen is formed in the overtube body, which extends from the distal end to the proximal end of the overtube body, the pulling lumen is configured to allow a pulling part to pass therethrough, and the distal end of the pulling part is fixed with the distal end of the overtube body.