To prevent the generation of fine powder chip generated by the contact friction of a cutting edge and cutting part of a long body by impregnating the cutting edge for cutting the long body moving in the cutting direction, with the lubricant or mold releasing agent for cutting the long body in a state that the lubricant or mold releasing agent is attached to the edge and/or the blade surface.

A sponge 12 or a sponge 13 as a cleaning member impregnated with the lubricant or mold releasing agent is mounted on a position to be contacted with a rotary round blade 2 on a moving passage of the rotary round blade 2 of a carriage 4 in its cutting direction (a). An edge and a blade surface of the rotary round blade 2 is contacted with the sponges 12, 13, and a photoresist film (long body) can be cut in a state that the lubricant or mold releasing agent is attached to the edge and the blade surface. Whereby the frictional resistance by the contact of a cut part of the long body and the blade can be reduced, the generation of the fine powder chip generated by the friction can be prevented, and the quality of the cut long body can be improved.