In a method for grinding a traction surface of a half-toroidal CVT disk, there is provided a grinding machine including a hold mechanism holding the half-toroidal CVT disk having a given machining allowance, and a machining mechanism including a tool for grinding the half-toroidal CVT disk. The grinding of said grinding machine is performed in a state that one of the half-toroidal CVT disk and said tool is inclined at a predetermined angle with respect to the other. A cutting angle, which is an angle to be formed by the cutting direction of said tool with respect to the axis of the half-toroidal CVT disk, is set to be in the range of ±15° with respect to the angle that a first cutting magnification at the time of that said tool contacts with an outer periphery position of the traction surface is substantially equal to a second cutting magnification at the time that said tool contacts with an inner periphery position of the traction surface, each of said first and second cutting magnifications being a ratio of an apparent machining allowance to the given machining allowance.