To unite pretreatment steps for a belt material prepared in a coiled form, including a preceding work step (actually a delivering step for belt material) into a single step.

A material 6 is delivered from a material feed part 7 and the material 6 is wound round a supporting surface 5, and while the material is being fed, the material 6 and part 7 are swingably supported to automatically adjust the angle of the winding of the material, and while the material 6 is being wound, tension thereof is maintained so that a cleaning treatment and a conditioning pretreatment are applied to the material 6 between a material delivering part and a material winding part, and moreover adhesives are applied to the material between both the parts.