To extend life by preventing selective wear of the blade body of a disc-shaped rotary cutting tool.

A cutting-blade chip 15 made of a high hardness sintered body is secured by soldering or the like to a chip seat 14 on the front surface 12a of a blade body along the direction of rotation, the blade body being provided on the outer periphery of the main body 11 of a chip saw. A blade body protection chip 16 makes close contact with the blade body leading to the chip seat and also with the portion between the inner end of the cutting-blade chip and the bottom of a blade chamber 13 and is bonded and fixed by soldering, etc. Since the radial inner part of the blade body to which the cutting-blade chip is not fixed is covered with the blade body protection chip, this portion of the blade body can be prevented from wearing during cutting work for cast products or the like that contain casting sand. The surface of contact 17 bonded by soldering or the like between the cutting-blade chip and the blade body protection chip is tilted 30 to 60 degrees in the direction of an axis relative to the circumferential direction whereby wear of the surface of contact is inhibited for enhanced durability of the chip saw. The surface of contact can also be protected by providing a front protecting part integral with the base part of the blade body protection chip.