Porous composite film, separator for battery, battery, and porous composite film production method

A porous composite film comprising a porous substrate and a porous layer laminated on at least one surface of the porous substrate, wherein the porous layer contains a fluorine-containing resin and satisfies (i), (ii), and (iii):

• (i) a value of D150 of a cross-sectional void area distribution of the porous layer is 0.06 μm2 or more and 0.38 μm2 or less, and a value of D190 of the cross-sectional void area distribution of the porous layer is 0.20 μm2 or more and 1.15 μm2 or less;
• (ii) a value of D250 of a surface pore area distribution of the porous layer is 0.0060 μm2 or more and 0.0072 μm2 or less, and a value of D290 of the surface pore area distribution of the porous layer is 0.0195 μm2 or more and 0.0220 μm2 or less;
• and
• (iii) porosity of the porous layer is 50% or more and 70% or less.