The present invention relates to a sealing tool for a pouch type secondary battery, which seals a pouch provided with an electrode assembly therein, the sealing tool including: a holder elevatably disposed on each of upper and lower sides of the pouch; and a sealing block coupled to the holder to contact the pouch by the elevation of the holder, thereby sealing the pouch. The sealing block and the holder are spaced apart from each other to define a space therebetween.According to the present invention, a spacing member is interposed between the holder and the sealing block of the sealing tool to define a space into which the sealing block is deformable, thereby minimizing the deformation of a sealing surface of the sealing block. Thus, the sealing part of the pouch may have a uniform thickness to prevent an electrolyte within the pouch from leaking to the outside.