PURPOSE: To prepare the titled mask having high precision micropatterns and yet sufficient strength, by repeating a step of metal plating in the holes of the figure made of a resist film as a protective film.

CONSTITUTION: Conductive metal film 22, such as a copper thin film is fabricated on silicon substrate 23, positive type resist film is attached onto film 22, imagewise exposed, and developed to form figure 21 made of the resist film (step 1). Metal 24, such as nickel to be used as a masking material is plated on the exposed parts of film 22 using film 22 as an electrode to form a plate not exceeding the height of figure 21 (step 2). The second resist film is attached to them 21, 24, likewise exposed and developed to form figure 25 made of the resist film (step 4), and plated to form metal film 26 (step 4). Steps 3, 4 are repeated desired times and substrate 23, electrode 22, and resist films 21 and 25 are removed to form self- supporting type metallic mask 27.