PURPOSE: To obtain homogeneous one side of machining scratches and to improve machining efficiencies in such a way that grinding pressure is applied to a grinding belt using a platen made of soft resilient material, and fine vibration is given to the platen in the feeding direction of the machined work.

CONSTITUTION: A grinding belt 6 is tensed between a platen 13 and an idler wheel 8, the belt 6 is sent by a motor 9, and its tensile force is adjusted by an air cylinder 10. The platen 13 is made of the one in which soft resilient material 17 is fixed into a sliding material 18, and fine vibration is made in the same direction to the feeding direction of a machined work 12 through a crank arm 14 along a slide ring 19 by a motor 15. When it is ground, first the machined work 12 is fed, put on the belt 11, with rise of a receiving stand 16, the determined notch is set. Then, grinding pressure is applied by the platen 13, at the same time as feed of the grinding belt 6 and reciprocation of the platen 13 are operated, the machined work 12 is fed.