A film having high lubricity and excellent dielectric strength characteristics and containing few fish eyes is obtained by biaxially-stretching a resin composition which has been obtained by radical polymerization of 0.5-80 parts by weight of a monomer component composed principally of a styrene monomer in the presence of 100 parts by weight of particles of a substantially straight-chain poly(arylene sulfide) having a melt viscosity of at least 1,000 poises.