Abstract: The present invention provides a separator for a non-aqueous electrolyte battery that includes a porous base material including a polyolefin and a heat-resistant porous layer provided on at least one surface of the porous base material and including a heat-resistant resin, in which when a thermomechanical analysis measurement has been performed by applying a constant load, the separator for a non-aqueous electrolyte battery satisfies the following conditions (i) and (ii): (i) at least one shrinkage peak appears in a temperature range of from 130 to 155° C. in a displacement waveform representing shrinkage displacement with respect to temperature; and (ii) an extension rate in a range from a shrinkage peak appearance temperature T1 to (T1+20)° C. is less than 0.5%/° C.