A work surface is ground by moving a grinding wheel, on an outer periphery of which a helical dressed groove having no intersection is formed, in a first direction being tilted with respect to a forward direction. Then, the work surface is ground by moving the grinding wheel in a second direction which is tilted with respect to a backward direction. When the grinding wheel is virtually moved for grinding in the forward direction, an extending direction of a virtual grinding trace formed by the dressed groove transcribed and the first direction are tilted in mutually opposite directions with respect to the forward direction. An absolute value of a tilt angle of the first direction is smaller than that of the extending direction of the virtual grinding trace. Rotation directions from the forward direction to the first direction and from the backward direction to the second direction are opposite.