PURPOSE: To prevent occurrence of dust from a resist and chromium in manufacture processes after development by exposing a positive resist in a specified width from the border of the mask blank after coating it with the resist, and developing this exposed part together with the exposed part for patterning and etching them.

CONSTITUTION: The mask blank 8 obtained by forming a chromium layer 3 on a glass substrate 4 is coated with the positive resist 2, the constant width L from the border of the blank is exposed to electron beams 1 at the same time of exposing for patterning, and the resist pattern 5 is formed by development 9, and the exposed resist part 6 of the circumference of the mask is removed by the development and etching 10, and likewise the chromium part 7 on the circumference of the mask is removed, thus permitting occurrence of dust due to friction of the resist and chromium with a conveying system in the following manufacturing processes to be prevented.