PURPOSE: To prevent that grinding refuse flies up into the air to again adhere to the other part of a work by catching and removing the grinding refuse bonded to the surface of the work by the dust removing roller of a dust removing mechanism and the varnish cloth pressed to the surface of the work.

CONSTITUTION: The surface of a car body is rubbed with the web like varnish cloth 47 wound around the dust removing roller 43 of a dust removing mechanism under predetermined surface pressure while the dust removing mechanism is controlled so as to move along the surface shape of the car body to catch the grinding refuse bonded to the surface of the car body by the varnish cloth 47. The varnish cloth 47 is successively driven from a delivery roller 46a to a take-up roller 46b by drive rollers 27a, 27b and, since the new varnish cloth 47 is always sent to the part of the dust removing roller 43, the grinding refuse is efficiently removed.