A stent delivery system, comprising: a connector portion connected to an external current source; an electrocautery tip connected to the connector portion by a conductive line; and a delivery portion having a first side connected to the electrocautery tip and a second side connected to the connector portion, the conductive line being accommodated in the delivery portion for connecting the electrocautery tip and the connector portion positioned therein, wherein the delivery portion includes a stent space portion accommodating a stent and formed adjacent to the electrocautery tip inside the delivery portion, and the delivery portion is configured to move to supply the stent into a human body tissue, wherein the electrocautery tip comprises: a tip electrode body being made of a conductive material and having a tip guide hole formed therein, the tip electrode body having an outer circumferential surface tapered to be narrower in a direction towards a distal end of the electrocautery tip and a proximal end connected to the conductive line; characterized in that a tip insulator having its distal end coupled to the proximal end of the tip electrode body, its outer circumferential surface tapered to be narrower in a direction opposite to the direction of the tip electrode body towards a proximal end of the electrocautery tip and its proximal end connected to the delivery portion; a coupling portion formed at the proximal end of the outer circumferential surface of the tip electrode body; and a variable-sized ring configured to be coupled to the coupling portion to vary a maximum diameter of the tip electrode body, wherein the coupling portion has a threaded outer surface, and the variable-sized ring has a threaded inner surface formed to correspond to the threaded outer surface of the coupling portion; wherein the outer circumferential surface of the variable ring is tapered; wherein one side of the outer circumferential surface of the variable ring is tapered in the same direction as the tip electrode body, and the other side of the outer circumferential surface of the variable ring is tapered in the same direction as the tip insulator. a connector portion connected to an external current source; an electrocautery tip connected to the connector portion by a conductive line; and a delivery portion having a first side connected to the electrocautery tip and a second side connected to the connector portion, the conductive line being accommodated in the delivery portion for connecting the electrocautery tip and the connector portion positioned therein, wherein the delivery portion includes a stent space portion accommodating a stent and formed adjacent to the electrocautery tip inside the delivery portion, and the delivery portion is configured to move to supply the stent into a human body tissue, wherein the electrocautery tip comprises: a tip electrode body being made of a conductive material and having a tip guide hole formed therein, the tip electrode body having an outer circumferential surface tapered to be narrower in a direction towards a distal end of the electrocautery tip and a proximal end connected to the conductive line; characterized in that a tip insulator having its distal end coupled to the proximal end of the tip electrode body, its outer circumferential surface tapered to be narrower in a direction opposite to the direction of the tip electrode body towards a proximal end of the electrocautery tip and its proximal end connected to the delivery portion; a coupling portion formed at the proximal end of the outer circumferential surface of the tip electrode body; and a variable-sized ring configured to be coupled to the coupling portion to vary a maximum diameter of the tip electrode body, wherein the coupling portion has a threaded outer surface, and the variable-sized ring has a threaded inner surface formed to correspond to the threaded outer surface of the coupling portion; wherein the outer circumferential surface of the variable ring is tapered; wherein one side of the outer circumferential surface of the variable ring is tapered in the same direction as the tip electrode body, and the other side of the outer circumferential surface of the variable ring is tapered in the same direction as the tip insulator. a tip electrode body being made of a conductive material and having a tip guide hole formed therein, the tip electrode body having an outer circumferential surface tapered to be narrower in a direction towards a distal end of the electrocautery tip and a proximal end connected to the conductive line; characterized in that a tip insulator having its distal end coupled to the proximal end of the tip electrode body, its outer circumferential surface tapered to be narrower in a direction opposite to the direction of the tip electrode body towards a proximal end of the electrocautery tip and its proximal end connected to the delivery portion; a coupling portion formed at the proximal end of the outer circumferential surface of the tip electrode body; and a variable-sized ring configured to be coupled to the coupling portion to vary a maximum diameter of the tip electrode body, wherein the coupling portion has a threaded outer surface, and the variable-sized ring has a threaded inner surface formed to correspond to the threaded outer surface of the coupling portion; wherein