MICROPOROUS FILM

A microporous film which is excellent in permeability and mechanical strength and has breakage resistance at high temperatures; a separator for a nonaqueous-electrolyte battery which comprises the microporous film; and a nonaqueous-electrolyte battery employing the separator. The microporous film has a gel content of from 20 to 90% as determined through 3-hour immersion in boiling xylene, and a modulus of elasticity at 150 DEG C of from 1 million to 100 millions Pa. The microporous film may also contain a resin having a crosslinked structure.