To suppress an affected layer regardless of the flow rate control on grinding fluid.

This grinding device 1 is provided with a wheel spindle stock 3 movably supported by a grinding machine body 7, a grinding wheel 5 supported by the wheel spindle stock 3 in a rotatable and drivable manner, which can be moved for grinding along with the movement of the wheel spindle stock 3, a servo motor 9 driving the wheel spindle stock 3 to permit grinding movement, and a controller 11 controlling the servo motor 9 so that work W supported on the grinding machine body 7 side is ground by the grinding wheel 5 in the grinding cycle of an in-feed and a spark-out grinding process. The controller 11 executes control on the servo motor 9 in a grinding cycle in consideration of the relationship between the amount of elastic deformation of the work W at the time of the completion of the in-feed grinding process, and the affected layer formed on the surface of the work W.