Abstract: A slitting equipment, piercing various patterns of ventilation slits in thin material, comprising a frame, a main cylinder, auxiliary cylinders, and a plate with knives. Upon an electric impulse from a bag-making machine, to which the present slitting equipment is attached, the auxiliary pneumatic cylinders press and stretch the thin material when the main pneumatic cylinder activates a plate, to which is attached a multitude of cutting knives, up and down the vertical plane. The sharp knives pierce and cut the stretched, thin film in the designed pattern. When the knives have disengaged from the material, the auxiliary cylinders release the film, and the latter is free to move horizontally, while restricted vertically by the top and bottom supports of the machine. As a result of this procedure, ventilation openings have been created simultaneously with the sealing and shaping processes carried on by the bag-making machine, without producing any waste material.