A method of manufacturing a shunt resistor that includes a resistance alloy plate member and first and second conductors respectively joined to one side and the other side in a planar direction that is perpendicular to a plate thickness direction of the resistance alloy plate member, comprising:
- a step of providing a resistance alloy plate member that has resistance-alloy-side first and second joining surfaces respectively arranged on one side and the other side in the planar direction;
- a step of providing a first conductor having first and second plate surfaces on one side and the other side in the plate thickness directions, respectively, and an end surface connecting edges of the first and second plate surfaces that are close to the resistance alloy plate, the first conductor having a thickness larger than that of the resistance alloy plate, the end surface of the first conductor including a first-conductor-side joining surface that comes into contact with the resistance-alloy-side first joining surface;
- a step of providing a second conductor having first and second plate surfaces on one side and the other side in the plate thickness directions, respectively, and an end surface connecting edges of the first and second plate surfaces that are close to the resistance alloy plate, the second conductor having a thickness larger than that of the resistance alloy plate, the end surface of the second conductor including a second-conductor-side joining surface that comes into contact with the resistance-alloy-side second joining surface;
- a first conductor welding process of causing the first-conductor-side joining surface and the resistance-alloy-side first joining surface to abut on each other, and then emitting electron beams or laser to the joining surfaces in the abutted state from one side in the plate thickness direction to weld the joining surfaces;
- and
- a second conductor welding process of causing the second-conductor-side joining surface and the resistance-alloy-side second joining surface to abut on each other, and then emitting electron beams or laser to the joining surfaces in the abutted state from one side in the plate thickness direction to weld the joining surfaces;
- wherein the end surface of the first conductor includes a first plate-thickness-direction extending surface extending from the edge of the first plate surface that is close to the resistance alloy plate toward the other side in the plate thickness direction, and the first-conductor-side joining surface is inclined so as to be gradually located on the side opposite from the resistance alloy plate member with respect to the plate surface direction from the first plate-thickness-direction extending surface toward the other side in the plate thickness direction and reach the second plate surface,
- wherein the end surface of the second conductor includes a first plate-thickness-direction extending surface extending from the edge of the first plate surface that is close to the resistance alloy plate toward the other side in the plate thickness direction, and the first-conductor-side joining surface is inclined so as to be gradually located on the side opposite from the resistance alloy plate member with respect to the plate surface direction from the first plate-thickness-direction extending surface toward the other side in the plate thickness direction and reach the second plate surface,
- wherein the resistance-alloy-side first and second joining surfaces are formed into inclined joining surfaces corresponding to the first-conductor-side joining surface and the second-conductor-side joining surface, respectively, and
- wherein, in the first conductor welding process and the second conductor welding process, the emission direction of the electron beams or the laser is set along the inclined joining surfaces.