The present invention relates to a composite porous separation membrane having a shut-down function imparted by a porous substrate, a method for manufacturing same, and secondary batteries using same, wherein, the ionic mobility of the composite porous separation membrane can be improved by setting the porosity (pore size) of the porous substrate which is used as a supporter as the same or similar to the porosity (pore size) of a web layer which is laminated on the porous substrate. The composite porous separation membrane of the present invention includes the porous substrate that acts as a supporter and has a first melting point and a first porosity; a first porous polymer web layer which is laminated on one side surface of the porous substrate and acts as an adhesive layer when put in close contact with an electrode in opposite orientation; and a second porous polymer web layer consisting of heat-resistant polymer nanofibers which are laminated on the other side surface of the porous substrate. The first porous polymer web layer and the second porous polymer web layer are characterized by having melting points higher than the first melting point of the porous substrate, and having a porosity that is the same as or similar to the first porosity.
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