PURPOSE: To grind a work roll as it is set in a rolling mill, by providing a grinding roll with a crown precisely fittable to a crown of a work roll, and by pressing this grinding roll to the work roll for grinding it.

CONSTITUTION: When a work roll 2 is abraded, a pusher driving mechanism 5 is started to strongly press a grinding roll 3 to the work roll 2 through an upholding beam 4. A brake 9 is then actuated to restrain the rotation of the grinding roll 3. Since the work roll 2 is rotating, a friction generates between a crown 13 of the work roll 2 and a crown 15 of the grinding roll 3 so that the work roll 2 is ground by the grinding roll 3 and is corrected to a prescribed crown. At the point of time as the crown 13 of the work roll 2 is corrected, the pusher driving mechanism 5 is withdrawn so as to separate the grinding roll 3 from the work roll 2, and the grinding work is completed.