PURPOSE: To easily perform cleaning of the interior wall surface of a trolley conveyor rail by installing a brush mounting member of radial construction to be in pressure contact with the rail interior wall surface on a trolley conveyor chain, and putting the brush mounting member in circulative motions.

CONSTITUTION: A trolley conveyor rail 10 is provided with a guide groove 10a formed in a chain pendant 14 stretching in the longitudinal direction in the upper part, and a trolley conveyor chain 12 is accommodated in the rail 10 with possibility of traveling freely, and a brush mounting member 20 fitted with brush in radial arrangement is coupled with the chain 12 in the specified position. The brush mounting member 20 is equipped with a roller joint 22 having a tine part and a brush joint 30 to be coupled internally with it rigidly. The chain pendant 14 is tracted by a traction drive motive, and the interior wall surface 10b of the rail is cleaned by putting the chain 12 and brush mounting member 20 in circulative motions, wherein the scratched-out oil gas and dust/dirt are dropped into and accommodated by an accommodation pan.