To facilitate the assembly work of a film forming mask device, and to eliminate deviation or defective film forming of material for forming the film.

This film forming mask device comprises a spacer 4 having storage holes 41 to store a plurality of crystal plates B and comprising a magnetic body with the crystal plate store in this storage hole, an upper mask 5 which is arranged above this spacer 4 and provided with an upper mask pattern for forming the film, and a lower mask 3 which is arranged below the spacer 4 and provided with a lower mask pattern for forming the film. A sheet-like magnet 7 which is closely attached between the spacer and the lower mask, exposes the mask pattern, and has through holes 71 corresponding to the storage holes in the spacer, is provided.