To provide a grinding apparatus which allows a footprint to be downsized.

A double wheel 35 is constructed by concentrically arranging a rough grinding wheel (a first wheel) 36 and a finishing grinding wheel (a second wheel) 37 having a larger diameter than the rough grinding wheel 36. A diameter D1 of the rough grinding wheel 36 has a length substantially the same as a radius r of a processed object 1, and a difference between a radius R2 of the finishing grinding wheel 37 and a radius R1 of the rough grinding wheel 36 is equal to or larger than the radius r of the processed object 1. When directing the rotated double wheel 35 toward the processed object 1 and descending the double wheel 35 to grind a processed surface 1a, outer peripheries of the grinding wheels 36 and 37 are positioned at a center of the processed object 1 to carry out grinding of the whole processed surface 1a, in each of the processes of rough grinding with the rough grinding wheel 36 and finishing grinding with the finishing grinding wheel 37.