PURPOSE: To prevent an interlayer from being formed and to reduce a stage for removing the interlayer by forming a 1st resist film on a film to be worked on a substrate and then forming a polymethyl methacrylate film.

CONSTITUTION: After novolak-based UV resist is applied on the surface of the film 22 to be worked on the semiconductor substrate 21 such as Si so as to form the 1st resist film 23, the PMMA film 24 is formed on the surface 23. Next, the pattern of the film 24 is developed and formed by directly plotting on the film 24 with an electron beam 25. Then, the film 24 is irradiated with UV light 26, and the pattern of the film 24 is transferred to the film 23 and developed. By dry etching the film 22 in a state where the films 23 and 24 are take as a mask, the pattern of the film 22 is formed. At such a time, the film 24 is removed by etching gas. Furthermore, the film 23 is removed and the pattern of the film 22 is formed on the substrate 21.