To enable a pattern which generates a phase shift to be optionally set in position and size by a method wherein a drawing operation is carried out with an electron beam varying exposure, and the pattern is formed through a development/ plating process and/or a development etching process.

A plating electrode layer 2 and a positive resist layer 3 are applied onto the surface of a mask board 1. A pattern is drawn by an electron beam 4 satisfying a formula, Da<Db, wherein Da represents the exposure of the periphery A of the pattern, and Db is the exposure of the center B of the pattern. Then, a developing operation is carried out setting an exposure time so as to enable resin to be completely removed from the center B but left unremoved in the periphery A. Then, a plating operation is carried out, a pattern 7 is formed only on the center B where the plating electrode layer 2 is exposed, an additional development operation is carried out, resist is completely removed from the periphery A to make the plating electrode 2 exposed, and a following plating process is carried out to form a pattern 7 in the periphery A. A resist 3 is removed by etching.