PURPOSE: To provide a method for welding the end plug of an fuel rod, by which grinding work after welding can be saved and the labor saving is obtd.

CONSTITUTION: The end plug 10 provided with a recessed part 11 is prepared and inserted into the end part of a coated pipe 1 and after positioning the inner peripheral surface of the recessed part 11 into the inside of the coated pipe 1, a first rotary electrode 12 is inserted into the recessed part 11. A second rotary electrode 13 is abutted on the outer peripheral surface at the end of the coated pipe 1 and the annular wall part 10A of the end plug 10 and the coated pipe 1 are interposed with both rotary electrodes 12, 13. Successively, the rotary electrode 12 is rotated, and while rotating the coated pipe 1 and the end plug 10, electric current is conducted between both rotary electrodes 12, 13 to seam-weld the inner peripheral surface of the coated pipe 1 and the outer peripheral surface of the end plug 10.