A masking film is provided to protect an area that should not be painted. A method for manufacturing the masking film requires extrusion-molding a film sheet in a tube shape; compressing the tube to create a twofold film sheet; folding the twofold film sheet in half by a first center line, to form a fourfold film sheet; folding the fourfold film sheet in half by a second center line, to form an eightfold film sheet; slitting an outermost film along a virtual slitting line positioned at a predetermined width inward from a folding line to form a plurality of leaves; and winding the film sheet about a bobbin with a slitting line slit positioned inwardly.