To provide a laminate film where cycloolefin layers having different glass transition points (Tg) are laminated and where oblique stripe failure, transverse failure, vertical stripe failure and corner unevenness are improved.

A laminate film produced by film-formation and lamination of a cycloolefin resin layer A and a cycloolefin resin layer B using a melt casting film forming method is characterized in that the glass transition temperature difference ΔTg (Tg(a)-Tg(b)) is 5°C or more when the glass transition temperature of the cycloolefin resin layer A is defined as Tg(a) and the glass transition temperature of the cycloolefin resin layer B is defined as Tg(b), and in that the melt flow rate of both the cycloolefin resin layer A and the cycloolefin resin layer B is 5 g/10 min or more and 50 g/10 min or less.