To provide a method of efficiently and highly accurately cutting an axis asymmetric optical plane.

The method is for machining the axis asymmetric optical plane having a plurality of approximately elliptic orbicular bands wherein the optical plane FO constituting each orbicular band is inclined with respect to a reference plane FR perpendicular to the optical axis, the closer to the outer periphery the orbicular band is located, the narrower the width is specified, and the larger the gradient angle α of the optical plane FO specified. The method comprises steps of driving to rotate a rotary tool 24 formed with a cutting edge 24a around the outer periphery, directing the axial line of a rotary shaft 22 in the direction of a normal line with respect to the inner periphery of the orbicular band, tilting the rotary shaft 22 of the rotary tool 24 according to the gradient angle α of the optical plane FO of the orbicular band to be machined, moving a work W in parallel to the reference plane FR while rotating it with respect to the tool 24 so that the tool 24 moves along the orbicular band to be machined, calculating whether the rotary tool 24 interferes with an adjacent orbicular band toward the outer periphery of the orbicular band to be machined, and, if it interferes, further tilting the rotary shaft 22 of the tool 24 according to the interference amount to avoid the interference.