Porous film manufacturing method and apparatus

A method of manufacturing a porous film, the method comprising:

• coagulating an undiluted film forming solution comprising a hydrophilic polymer and a hydrophobic polymer, thereby obtaining a porous film precursor;
• consecutively introducing the porous film precursor into a decomposition container;
• bringing a heated chemical comprising an oxidizing agent into contact with the porous film precursor in the decomposition container, wherein the decomposition container is warmed by a vapor;
• warming the porous film precursor in contact with the chemical by traveling the porous film precursor in the vapor phase;
• decomposing the hydrophilic polymer remaining inside the porous film precursor in the presence of the oxidizing agent, and
• discharging the porous film precursor from the decomposition container.