PURPOSE: To make a required roller detachable by forming an upper opening supporting part of an upward facing guide surface and a side cover in a chain guide rail, and attaching and detaching a link pin which links a roller with a chain with the engaging hole of an edge part cap which is engaged on a free roller edge side through a slit.

CONSTITUTION: A guide rail 22 which is disposed at each side of a transportation passage is formed of an upward guide surface 22a and a side cover part 22b, a chain 19 is supported by the upward guide surface 22a to prevent lateral deflection of the chain 19 with the side cover part 22b. Besides, the guide rail is installed with an edge part cap 20B integratedly engaged inside with both edges of a roller 20 which is installed to the chain 19. A slit part 20E where the engaging hole 20C of a link pin 19A and the link pin 19A can be detached in a vertical direction is formed in the edge part cap 20B. It is thus possible to raise the chain with the slip part of the roller upward, and then remove only the required roller after traveling sideward.