The involute cam is used for generating tooth form of an involute gear in gear grinder with involute cam-link stopper, and its profile error is one of the factors which decide the tooth form precision of gear. The conventional processing means of involute cams can't achieve a sufficient accuracy. In this paper, a double-disc mode grinding device is introduced. Based on analysis of grinding principle, the device's structure and working process are described, and the main sources of grinding profile errors are analyzed. It is confirmed that the introduced device has the ability of accomplishing a highly precise grinding of involute cams.