To improve face roughness regardless of a tool shape and even if a work is not rotated at a high speed.

This cutting method is used for cutting the work by operating, to the work mounted to a main spindle rotating about a C-axis, a tool mounted to a spindle of a spindle unit mounted to a Z-axis slide movable in the Z-axis direction parallel with a shaft core of a main spindle and fixed to an X-axis slide movable in the X-axis direction orthogonal to the shaft core of the main spindle. The work is partially cut by rotation of the tool, this cut region is overlapped to the C-axis and the Z-axis with tool rotation speed at least 102 higher than a work rotation speed, and the overlapping part is enlarged to the entire machined region of the work.