A propulsion assembly is for an endoscope having an elongated tube for entry in a tube of a body cavity. The propulsion assembly includes endless belts for contacting a surface of the body cavity, for propulsion by turning around in an axial direction of the elongated tube. A support sleeve supports the endless belts movably. A distal cover frame is secured to a distal side of the support sleeve. An idler roller is contained in the distal cover frame, engaged with a distal end of the endless belts, for regulating the endless belts in the axial direction. A proximal cover frame is secured to a proximal side of the support sleeve. A driving roller is contained in the proximal cover frame, engaged with a proximal end of the endless belts, for regulating the endless belts in the axial direction. The driving roller drives the endless belts.
