GRINDING METHOD OF WORKPIECE

To reduce deterioration in the condition of a second grinding stone.SOLUTION: A grinding method of workpiece includes a first grinding step of grinding workpiece by a first grinding wheel having a plurality of first grinding stones, and a second grinding step of grinding the workpiece by a second grinding wheel having a plurality of second grinding stones having abrasive grains having the average particle diameter smaller than the average particle diameter of abrasive grains of the respective first grinding stones, wherein the first grinding step includes an upper face side grinding step of grinding the upper face side of the workpiece in a state in which the loci of the plurality of first grinding stones overlap the center of a first holding surface in a rotation axis direction of the first grinding wheel, and a projection formation step of grinding an annular region on the upper face side of the workpiece in a state where the loci of the plurality of first grinding stones do not overlap the center of the first holding surface in the rotation axis direction of the first grinding wheel, and thereby forming a disk-like projection in the central part of the workpiece, wherein the second grinding step sequentially grinds the projection and the annular region by the second grinding wheel.SELECTED DRAWING: Figure 1 【課題】第２研削砥石のコンディションの悪化を低減する。【解決手段】複数の第１研削砥石を有する第１研削ホイールで被加工物を研削する第１研削ステップと、各第１研削砥石の砥粒の平均粒径よりも平均粒径が小さい砥粒をそれぞれ有する複数の第２研削砥石を有する第２研削ホイールで被加工物を研削する第２研削ステップと、を備え、第１研削ステップは、複数の第１研削砥石の軌跡を第１研削ホイールの回転軸方向において第１保持面の中心と重ねた状態で、被加工物の上面側を研削する上面側研削ステップと、複数の第１研削砥石の軌跡を第１研削ホイールの回転軸方向において第１保持面の中心と重なない状態で被加工物の上面側の環状領域を研削することにより、円板状の凸部を被加工物の中央部に形成する凸部形成ステップと、を含み、第２研削ステップでは、凸部と環状領域とを第２研削ホイールで順次研削する被加工物の研削方法を提供する。【選択図】図１