A method for manufacturing an insert-molded bus bar comprising the steps of: preparing a first bus bar having a through hole and a second bus bar having a protrusion corresponding to the through hole; preparing a mold having therein a swaging member capable of swaging the protrusion, wherein the mold includes a first upper die and a second upper die, wherein the swaging member is movably placed in a space located in the middle of the first upper die with a predetermined region of movement, and wherein a resilient member is placed in the region of movement, and is biased so that the swaging member is not moved when the first upper die and the second upper die are in contact with each other, while the swaging member is moved upward when the first upper die and the second upper die are separated from each other; placing the first and second bus bars (10, 14) in the mold with the protrusion of the second bus bar being inserted into the through hole in the first bus bar; pressing the protrusion of the second bus bar so as to be larger than the diameter of the through hole in the first bus bar, and deforming the protrusion into a swaged region that is tightly caught on a part of an upper surface of the first bus bar using the swaging member of the mold so as to obtain connected bus bars that are the bus bars connected to each other; forming a predetermined clearance between a swaging surface of the swaging member and a surface of the swaged region by moving the second upper die upward a predetermined distance from the first upper die, such that the swaging member is moved upward a predetermined distance by the resilient member provided in the region of movement; and injecting a molding material into the mold so as to cover the swaged region of the connected bus bars that are the bus bars connected to each other by swaging to perform insert molding using the mold and obtain the insert-molded bus bar. preparing a first bus bar having a through hole and a second bus bar having a protrusion corresponding to the through hole; preparing a mold having therein a swaging member capable of swaging the protrusion, wherein the mold includes a first upper die and a second upper die, wherein the swaging member is movably placed in a space located in the middle of the first upper die with a predetermined region of movement, and wherein a resilient member is placed in the region of movement, and is biased so that the swaging member is not moved when the first upper die and the second upper die are in contact with each other, while the swaging member is moved upward when the first upper die and the second upper die are separated from each other; placing the first and second bus bars (10, 14) in the mold with the protrusion of the second bus bar being inserted into the through hole in the first bus bar; pressing the protrusion of the second bus bar so as to be larger than the diameter of the through hole in the first bus bar, and deforming the protrusion into a swaged region that is tightly caught on a part of an upper surface of the first bus bar using the swaging member of the mold so as to obtain connected bus bars that are the bus bars connected to each other; forming a predetermined clearance between a swaging surface of the swaging member and a surface of the swaged region by moving the second upper die upward a predetermined distance from the first upper die, such that the swaging member is moved upward a predetermined distance by the resilient member provided in the region of movement; and injecting a molding material into the mold so as to cover the swaged region of the connected bus bars that are the bus bars connected to each other by swaging to perform insert molding using the mold and obtain the insert-molded bus bar.