PURPOSE: To facilitate the fitting/removing work of a self-propelled elevator by having a pair of the right and left crawlers and a holding roller in contact with the cylinder surface on the opposite side to a traveling device.

CONSTITUTION: The pinching angle θ of a traveling device and the length of the arm 24 of a holding device 3 are adjusted in response to the diameter of an erected cylinder 7. Next, the traveling device 1 is arranged along the erected cylinder 7 so that a pair of the right and left crawlers 14, 14 are brought into contact with the surface of the erected cylinder 7, the roller 23 of the holding device 3 is brought into contact with the surface of the erected cylinder 7 on the opposite side to the traveling device 1, then handles 31 are operated to rotate eccentric cams 29, and two crawlers 14 are maintained in contact with the erected cylinder by a holding roller 23. Accordingly, two crawlers 14 are uniformly brought into contact with the surface of the cylinder 7, and the straight forward property of an elevator can be secured.