A cylindrical battery cell comprising: a jelly-roll type electrode assembly, configured to have a structure in which a positive electrode and a negative electrode are wound in a state in which a separator is disposed between the positive electrode and the negative electrode; a cylindrical battery case having no beading part; a cap assembly located at an open upper end of the cylindrical battery case; and a gasket mounted so as to surround an outer circumference of a safety vent and a portion of a lower surface of the safety vent in order to maintain insulation between the cap assembly and the cylindrical battery case, wherein the cap assembly comprises the safety vent, which is configured to rupture in order to exhaust gas when a pressure in the cylindrical battery case increases, a cap plate mounted on the safety vent, the cap plate having formed therein through holes for discharging gas, and a current interrupt member attached to a lower end of the safety vent for interrupting current when the pressure in the cylindrical battery case increases, and wherein the gasket is coupled to a washer for fixing the cap assembly, and the washer is located on an outer circumferential portion of an open upper surface of the cylindrical battery case, and wherein the gasket is coupled to the washer via a thermoplastic adhesive layer, and wherein the washer has an outer diameter equal to an outer diameter of the cylindrical battery case, wherein the gasket is configured to have a structure comprising: a first coupling part, coupled to an outer circumferential portion of a lower surface of the current interrupt member; a step part, bent upwards perpendicularly from an outer circumference of the first coupling part; a second coupling part, bent outwards from an upper part of the step part so as to be parallel to the first coupling part and coupled to a lower surface of the safety vent; a third coupling part, bent upwards perpendicularly from an outer circumference of the second coupling part and coupled to an outer circumference of the safety vent and to an outer circumference of the cap plate; and a fourth coupling part, coupled to the washer so as to serve as an upper outer circumference of the third coupling part. a jelly-roll type electrode assembly, configured to have a structure in which a positive electrode and a negative electrode are wound in a state in which a separator is disposed between the positive electrode and the negative electrode; a cylindrical battery case having no beading part; a cap assembly located at an open upper end of the cylindrical battery case; and a gasket mounted so as to surround an outer circumference of a safety vent and a portion of a lower surface of the safety vent in order to maintain insulation between the cap assembly and the cylindrical battery case, wherein the cap assembly comprises the safety vent, which is configured to rupture in order to exhaust gas when a pressure in the cylindrical battery case increases, a cap plate mounted on the safety vent, the cap plate having formed therein through holes for discharging gas, and a current interrupt member attached to a lower end of the safety vent for interrupting current when the pressure in the cylindrical battery case increases, and wherein the gasket is coupled to a washer for fixing the cap assembly, and the washer is located on an outer circumferential portion of an open upper surface of the cylindrical battery case, and wherein the gasket is coupled to the washer via a thermoplastic adhesive layer, and wherein the washer has an outer diameter equal to an outer diameter of the cylindrical battery case, wherein the gasket is configured to have a structure comprising: a first coupling part, coupled to an outer circumferential portion of a lower surface of the current interrupt member; a step part, bent upwards perpendicularly from an outer circumference of the first coupling part; a second coupling part, bent outwards from an upper part of the step part so as to be parallel to the first coupling part and coupled to a lower surface of the safety vent; a third coupling part, bent upwards perpendicularly from an outer circumference of the second coupling part and coupled to an outer circumference of the safety vent and to an outer circumference of the cap plate; and a fourth coupling part, coupled to the washer so as to serve as an upper outer circumference of the third coupling part. a first coupling part, coupled to an outer circumferential portion of a lower surface of the current interrupt member; a step part, bent upwards perpendicularly from an outer circumference of the first coupling part; a second coupling part, bent outwards from an upper part of the step part so as to be parallel to the first coupling part and coupled to a lower surface of the safety vent; a third coupling part, bent upwards perpendicularly from an outer circumference of the second coupling part and coupled to an outer circumference of the safety vent and to an outer circumference of the cap plate; and a fourth coupling part, coupled to the washer so as to serve as an upper outer circumference of the third coupling part.