A sealing apparatus for sealing a sealing-planned part of a battery case comprising a protruding electrode lead, by applying heat and pressure to a battery cell having a structure in which an electrode assembly and an electrolyte solution are embedded in a battery case of a laminate sheet, wherein the electrode lead includes an electrically conductive lead member and a pair of insulating films attached in a form of locally surrounding the lead member; the insulating films include a surplus bonding part bonded to each other at both side end portions of the lead member; in the electrode lead, in a state in which a portion of the insulating films is in close contact with an inner surface of the sealing-planned part, a remaining portion of the electrode lead protrudes outwardly from the insulating film; wherein the sealing apparatus includes a pair of sealing blocks suitable for bonding the sealing-planned part by applying pressure and heat to the sealing-planned part at an upper portion and a lower portion of the sealing-planned part and the electrode lead protruding from the sealing-planned part, the electrode lead being interposed between the sealing-planned part; the sealing blocks are formed with two or more protrusion parts each extending in a direction towards the electrode assembly and in a direction opposite to the electrode assembly; wherein the sealing blocks further suitable for bonding the sealing-planned part and the insulating films that are in close contact with each other, and the protrusion parts further suitable for bonding the sealing-planned part extending along the end portion of the lead member and the insulating film exposed to the outside from the sealing-planned part; and wherein the protrusion part further suitable for applying heat and pressure to a corresponding portion of the sealing-planned part extending along an end portion of the electrode lead by heat and pressure of the sealing blocks, thereby sealing the extended sealing-planned part wherein the sealing blocks include a first block that is configured to pressurize the sealing-planned part at an upper portion; and a second block that is configured to pressurize the sealing-planned part at a lower portion, the protrusion parts are formed in the first block and the second block, respectively, inner portions of the first block, the second block, and the respective protrusion parts have heating means, the protrusions parts of both sealing blocks extend from the sealing block in both directions perpendicular to the direction that the sealing blocks oppose each other, the protrusions parts of opposing first and second sealing blocks face each other along the direction that the sealing blocks oppose each other, each of the first block and the second block includes a pair of first steps formed at positions corresponding to both side end portions of the electrode lead on a cross section perpendicular to direction that the sealing blocks oppose each other; and second steps extending from the first steps in a direction parallel to the direction that the sealing blocks oppose each other, respectively, and formed at positions corresponding to both side end portions of the surplus bonding part in the insulating film, and the protrusion parts of the first block and the second block include, in each of the first steps, a pair of first protrusion parts (310a, 310b) protruding toward the electrode assembly; and a pair of second protrusion parts (312a, 312b) protruding in opposition to the first protrusion parts (310a, 310b), and the protrusion parts of the first block and the second block also further include, in each of the second steps, a pair of third protrusion parts (320a, 320b) protruding toward the electrode assembly; and a pair of fourth protrusion parts (322a, 322b) protruding in opposition to the third protrusion parts (320a, 320b).