PURPOSE: To aim at improvement in grinding efficiency, by making a cylindrical grinding wheel rotate in the center of an axial center in a direction to be crossed with a work axial center, and forming a curve corresponding to the outer circumference, in the case of turning curved surface for a work end face.

CONSTITUTION: A work spindle 6 is driven into rotation by a motor 5b via a wrapping connector device 5a, and a work W being held by a collet chuck 7 is rotated as well. Simultaneously with this, a wheel spindle 12 is driven into rotation by a motor 11b and a wrapping connector device 11a, and a cylindrical grinding wheel G is rotated around an axial center ion the direction crossed with a axial center 2 of the work W whereby the outer circumference is formed into the form corresponding to a turning curved surface of an end face of the work W by a wheel former 18. And a wheel spindle stock 11 is moved by a pulse motor 17 via a feed screw 15, and an end face 1 of the work W is cut in with the periphery formed with the cylindrical grinding wheel G, thus it is ground into the desired turning curved surface. Doing like this, the cylindrical grinding wheel is no longer largely moved, and that since a large diametral grinding wheel is usable, so that grinding efficiency is sharply improvable.