To obtain a laminated film excellent in interlaminar adhesiveness by extruding a laminating resin to directly laminate the molten film thereof to a polyester film without applying anchor coating treatment to the polyester film and applying ozone treatment to the molten film of the extruded laminating resin.

An ethylene copolymer containing 1-12 wt.% of unsaturated carboxylic acid and 2-25 wt.% of (meth)acrylic ester or a compsn. prepared by compounding a small amt. of an ethylene/α-olefin copolymer with a density of 840-900 kg/m3 with the ethylene copolymer is extruded to be laminated to a polyester film.