A sealing apparatus for a secondary battery, adapted to seal a sealing part of a case in which an electrode assembly and an electrolyte are accommodated, the sealing apparatus comprising: a sealing member comprising a first sealing piece and a second sealing piece , adapted to thermally fuse a surface of the sealing part to seal the sealing part , wherein the first sealing piece and the second sealing piece comprise a plurality of thermal fusion parts , which are disposed from an outer end of a surface of the sealing part toward an inner end that is opposite to the outer end to thermally fuse the surface of the sealing part , and non-thermal fusion parts , which are disposed between the plurality of thermal fusion parts , are provided as an opening groove that is opened in a direction of the surface of the sealing part and do not seal the surface of the sealing part , characterized in that the thermal fusion part disposed on the inner end of the sealing part has an upward inclined surface (211a-1, 212a-1) that is inclined toward the inner end of the sealing part , and the upward inclined surface gradually decreases pressing force toward the inner end of the sealing part to deform a width of the inner end of the sealing part so that the width gradually increases; the thermal fusion part disposed on the outer end of the sealing part has a downward inclined surface (211a-2, 212a-2) that is inclined toward the outer end of the sealing part , and the downward inclined surface gradually increases pressing force toward the outer end of the sealing part to deform a shape of the outer end of the sealing part into a sharp shape; and wherein the non-thermal fusion part of the first sealing piece and the non-thermal fusion part of the second sealing piece are disposed to correspond to each other. a sealing member comprising a first sealing piece and a second sealing piece , adapted to thermally fuse a surface of the sealing part to seal the sealing part , wherein the first sealing piece and the second sealing piece comprise a plurality of thermal fusion parts , which are disposed from an outer end of a surface of the sealing part toward an inner end that is opposite to the outer end to thermally fuse the surface of the sealing part , and non-thermal fusion parts , which are disposed between the plurality of thermal fusion parts , are provided as an opening groove that is opened in a direction of the surface of the sealing part and do not seal the surface of the sealing part , characterized in that the thermal fusion part disposed on the inner end of the sealing part has an upward inclined surface (211a-1, 212a-1) that is inclined toward the inner end of the sealing part , and the upward inclined surface gradually decreases pressing force toward the inner end of the sealing part to deform a width of the inner end of the sealing part so that the width gradually increases; the thermal fusion part disposed on the outer end of the sealing part has a downward inclined surface (211a-2, 212a-2) that is inclined toward the outer end of the sealing part , and the downward inclined surface gradually increases pressing force toward the outer end of the sealing part to deform a shape of the outer end of the sealing part into a sharp shape; and wherein the non-thermal fusion part of the first sealing piece and the non-thermal fusion part of the second sealing piece are disposed to correspond to each other. <EOS>