A production method for preparing a porous film of a poly(vinylidene fluoride) based resin which has a microstructure providing a satisfactory mechanical strength and permeation performance and is improved in hydrophilic property, without the precise control of temperature before cooling, as well as a porous film prepared by the above method is provided. The above method for producing a porous film wherein a porous film of a poly(vinylidene fluoride) based resin is prepared by dissolving the poly(vinylidene fluoride) based resin in a poor solvent through heating to form a liquid raw material for a film, and then cooling the liquid raw material to bring about a phase separation is characterized in that an organized clay being organized by a hydrophilic compound is dispersed in said liquid raw material for a film in an amount of 1 to 25 parts by weight relative to 100 parts by weight of the poly(vinylidene fluoride) based resin.