Disclosed is a pouch-type secondary battery. The pouch-type secondary battery according to the present disclosure includes an electrode assembly comprising a cathode plate and an anode plate and a separator interposed between the cathode plate and the anode plate; and a pouch-type case formed by receiving and packaging the electrode assembly and an electrolyte solution inside, the pouch-type case having a sealing part formed along a circumference thereof, wherein a water permeation prevention member is attached to the entire sealing part formed along the circumference of the pouch-type case by welding.