PURPOSE: To feed plenty of grinding liquid to near the grinding position so as to prevent a grinding burning owing to the shortage of feeding grinding liquid in the groove grinding of the inner race or the like of a constant velocity joint, and lowering of service life of a grinding wheel, and to cut off the air flow generated by the high speed rotation of the grinding wheel so as to increase the feeding of the grinding liquid.

CONSTITUTION: This groove processing device is provided with grinding liquid feeding nozzles 30 and 31 to feed the grinding liquid to the grinding position 8 from the left side and the right side of a grinding wheel 22, and a grinding liquid injection device 40 to inject the grinding liquid to the grinding wheel 22 from the upper side so as to cut off the air flow.