To provide a polylactic acid film that is mainly composed of polylactic acid and exhibits high heat resistance, and to provide further a film having a wide application range as a sealing film and exhibiting excellent mechanical aptitude by laminating a sealant layer thereon.

The polylactic acid film is obtained by subjecting a polylactic acid film having a substrate layer that is mainly composed of a polylactic acid resin (A) having a molar ratio of an L-lactic acid unit to a D-lactic acid unit of 96/4 to 100/0 or 4/96 to 0/100 and has a plane orientation degree P of 110-4P310-3 to a heat treatment at a temperature T(C) within the temperature range below. The range of the heat treatment temperature T(C): Tg-30TTg+10 (wherein Tg is the glass transition temperature (C) of the polylactic acid resin (A)).