To provide a mold-release film excellent in surface smoothness, especially, in surface smoothness at a time of high temp. and useful for a resin sheet or film molded from a resin soln., a molding carrier film such as a ceramic sheet or the like molded from a ceramic slurry or a protective film of a self-adhesive layer of a self-adhesive tape or the like.

A mold-release film comprises a polyalkylene 2,6- naphthalenedicarboxylate containing 0.005-5 wt.% of inert particles and is characterized by that the absolute value of the dimensional change ratio of the mold- release film under a stress of 150 gf/mm2 at 120°C is 0.2% or less in both of longitudinal and vertical directions and the number of particles with a particle size of 50 μm or less in the film is 100/m2 or less and the surface roughness of the mold-release surface of the film is 2-50 nm.