Stretched laminated film for use in piezoelectric polymer material, and manufacturing method thereof

The purpose of the present invention is to provide a laminate film, and a manufacturing method thereof, which comprises polylactic acid and, while having excellent piezoelectric properties, is not prone to peeling. This stretched laminated film for use in a piezoelectric polymer material is obtained by coextrusion and comprises a layer (A) which has poly-L-lactic acid as the primary component and contains 0.1-10 mass% of an impact modifier, and a layer (B) which has poly-D-lactic acid as the primary component and contains 0.1-10 mass% of an impact modifier.