A microporous composite membrane obtained by coating at least one surface of a microporous polyolefin membrane with a solution of a gelable fluororesin in a mixed solvent of a good solvent for the fluororesin, and a poor solvent having a dipole moment of 1.8 Debye or less and drying to form a porous coating layer of the above fluororesin has cylindrical penetrating pores formed in the above coating layer, with well-balanced permeability, adhesion to electrodes, mechanical strength, heat shrinkage resistance, shutdown properties and meltdown properties.