In a machining method of supporting a workpiece having a cylindrical machined portion such that the workpiece is rotatable and feeding a grinding wheel in a radial direction, a start diameter that is a diameter including a measurement start point on a surface of the machined portion is measured, and, after the measurement start point passes through a machining application portion, an end diameter that is a diameter including a measurement end point is measured. An actual grinding depth at the time when the measurement start point is machined is computed by the equation, U=|D0−D1|, a runout of the machined portion is computed from a relative difference in the actual grinding depth (U) between positions of the machined portion in a rotational direction, and infeed control of the grinding wheel is executed such that the runout is removed.
