Method of grinding workpiece

A method of grinding a surface of a workpiece that has surface irregularities with grindstones, comprising:

• a holding step of holding the workpiece on a chuck table;
• a first grinding step of rotating the workpiece held on the chuck table and grinding the surface of the workpiece with the grindstones by a predetermined amount of stock removal while keeping a measuring element of a height gauge out of contact with the surface of the workpiece;
• a height difference measuring step of bringing the measuring element of the height gauge into contact with the surface of the workpiece that has been ground in the first grinding step and measuring a height difference of the surface irregularities on the surface of the workpiece with the height gauge;
• and
• a second grinding step of, if the height difference measured in the height difference measuring step falls within a preset range, stopping grinding the surface of the workpiece, and, if the measured height difference is larger than the preset range, grinding the surface of the workpiece while keeping the measuring element of the height gauge in contact with the surface of the workpiece until the measured height difference falls within the preset range.