A method of manufacturing a spark plug for an internal combustion engine, wherein in the spark plug, a center electrode and a ground electrode are opposed to each other with a spark discharge gap formed therebetween, and at least one of the center and ground electrodes (2, 3) has a discharge chip (4, 5) joined to an electrode base member (20, 30) that is made of a Ni alloy, so as to protrude toward the spark discharge gap, the method comprising: a chip making step of making the discharge chip (4, 5) by joining a discharge part (41, 51) and a base member-joining part (42, 52) to each other, the discharge part (41, 51) being arranged on the spark discharge gap side, the base member-joining part (42, 52) being made of a Ni alloy having a lower melting point than the discharge part (41, 51) and to be joined to the electrode base member (20, 30); a temporary joining step of temporarily joining the discharge chip (4, 5), at the base member-joining part (42, 52), to the electrode base member (20, 30) by resistance welding, and a main joining step of joining, by laser welding, the discharge chip (4, 5) to the electrode base member (20, 30) so that a side surface (411, 511) of the discharge part (41, 51) and a surface (22, 31) of the electrode base member (20, 30) are smoothly connected by a connecting surface (423, 523) that has no sharp edge, wherein in the main joining step, part of the base member joining part (42, 52) and part of the electrode base member (20, 30) are melted without melting the discharge part (41, 51), in the discharge chip (4, 5) obtained in the chip making step, a diameter of the base member-joining part (42, 52) is greater than a diameter of the discharge part (41, 51), and in the main joining step, the laser welding is performed at a temperature lower than the melting point of the discharge part (41, 51). a chip making step of making the discharge chip (4, 5) by joining a discharge part (41, 51) and a base member-joining part (42, 52) to each other, the discharge part (41, 51) being arranged on the spark discharge gap side, the base member-joining part (42, 52) being made of a Ni alloy having a lower melting point than the discharge part (41, 51) and to be joined to the electrode base member (20, 30); a temporary joining step of temporarily joining the discharge chip (4, 5), at the base member-joining part (42, 52), to the electrode base member (20, 30) by resistance welding, and a main joining step of joining, by laser welding, the discharge chip (4, 5) to the electrode base member (20, 30) so that a side surface (411, 511) of the discharge part (41, 51) and a surface (22, 31) of the electrode base member (20, 30) are smoothly connected by a connecting surface (423, 523) that has no sharp edge, wherein in the main joining step, part of the base member joining part (42, 52) and part of the electrode base member (20, 30) are melted without melting the discharge part (41, 51), in the discharge chip (4, 5) obtained in the chip making step, a diameter of the base member-joining part (42, 52) is greater than a diameter of the discharge part (41, 51), and in the main joining step, the laser welding is performed at a temperature lower than the melting point of the discharge part (41, 51).