PURPOSE: To enhance the efficiency of grinding in such an arrangement that a roll barrel is ground with the use of a cambering curve, by providing a control device which delivers an output cambering signal by synthesizing linear and quadratic functions having factors which may be arbitrarily set.

CONSTITUTION: In a control device for grinding a roll barrel along a cambering curve with the use of a grinding tool 10 which is swung about a shaft 11 as a fulcrum point by an eccentric cam 12 rotated by a cambering motor 13, there are provided setting units 33, 36, 41 for setting the rectilinear section B of the cambering curve, and factors U, V of the linear and quadratic functions of the cambering curve. Further, there are provided a control circuit 32 for delivering, when a count value on a counter display circuit 31 exceeds a set value B, an output pulse signal X-B which is the amount in excee of the value B, and a multiplier 35 for multiplying the pulse signal by the factor V. Further more, there is provided a multiplier 42 for obtaining a cambering signal 2U+V.1X- B2 from the thus obtained multiplied value and the factor U. The motor 13 is controlled by the output of the multiplier 42.