There are provided a microporous film for an electric storage device separator, which can increase energy density and power density when used in an electric storage device, and which is excellent in handling properties in a processing step to the electric storage device, as well as an electric storage device separator and an electric storage device, using the microporous film. Specifically, provided is a microporous film for an electric storage device separator, characterized by including a porosity of 70% or more, a strength of 40 MPa or more in a longitudinal direction, an average pore size of from 40 to 400 nm, anuclear pores, and exhibiting biaxial orientation.