PURPOSE: A gang form assembly is provided to allow a clamp unit to simply fix or unfix a sash for a window frame to a gang form using the pressure of pressing units. CONSTITUTION: A gang form assembly comprises a cage unit(2), a molding form(4), and a clamp unit(8). The cage unit has a scaffold(P). The molding form is attached on the side surface of the cage unit and has a flat molding surface(S) in which a sash for a window is arranged. The clamp unit is composed of pressing units(F) corresponding to the inner edge surface of the sash and fix or unfix the sash to/from the molding form.
