To highly accurately and uniformly grind and process a recessed part of a spherical shape having a predetermined radius of curvature and surface accuracy on a molding surface.

This grinding processing device has a main spindle 7 for installing a work, a grinding spindle 9 slantingly arrangeable to the main spindle 7, a grinding wheel 13 installed on the grinding spindle 9, a grinding spindle holder 12 for substantially integrally revolving and moving the grinding wheel 13 with the work in a state of setting a distance between the main spindle 7 and the processing center of the work substantially constant by pushing the grinding wheel 13 against the work, and a sensor 35 for measuring dimensional accuracy of the processed recessed part of the spherical shape. An inclination of the grinding spindle 9 is corrected by feeding back a measuring result by the sensor 35 to a rotary table 10 via a control part 36.