An apparatus for fabricating a pre-press masking film used for correcting a color printing plate which is slightly tilted by a scanner based on an image edited by a layout system. The apparatus includes a coordinate data input unit for inputting coordinate data defining a trimming frame designated by the layout system, a tilt correcting unit for compensating for the tilt of the color printing plate by correcting the coordinate data, a unit for generating driving signals for forming a pre-press masking film based on the corrected coordinate data, and a cutter unit responsive to the driving signal for forming a pre-press masking film for cutting the masking film.