The subject innovation relates to a surface preparative rotary cutter to be mounted on the power tools or air tools deurilcheok is provided, more particularly around the body with the cylindrical portion and the back has the support of the disk-like guide plate and the bag portion integrally of a round bar-shaped formed and the front and around the front central portion projecting each supporting ring and cutter blade insert portion of the support guide plate formed with and is equipped with a cutter blade holders ball bolt formed at the center said cutter blade insertion portion, the cutter of the cutter blade holder day insertion portion has formed in a truncated conical shape and is inserted through hole formed to be inserted into the cutter blade inserted part of the cutter blade holder in the central portion is equipped with a cutter blade is a plurality of the cutting edge portion is formed in the outer peripheral surface, the bolt fastening of the cutter blade holder ball has high speed by a support guide plate and the cutter guide bearing the day of fixing bolts of the cutter blade holder during chamfering work on the cut edges of by configuring it so that it locks the bolt fastening the day provided a guide bearing on the lower end outer circumferential surface of the cutter, steel plates and pipes to allow rotating the cutter blade can maintain a stable supporting state because it not only to be able to significantly improve the processing quality and workability, due to the long time use the cutter blade is only necessary the cutter blade without replacing the entire rotary cutter when worn It can be separated and replaced if it relates to a rotary cutter for preparative due to replacement by a full rotary cutter wear while at the same time to help reduce material costs significantly completely eliminate the problem of waste of the expensive material.