A repair welding device comprising: an inspection result acquisition unit configured to acquire an appearance inspection result including information about a defective portion of a weld bead (BD1, BD2) of a welded workpiece (Wk) produced by a main welding that is executed by a welding robot; and characterized by a robot control unit configured to instruct the welding robot to execute a repair welding on a position of the defective portion using the appearance inspection result based on a relationship between the position of the defective portion and a predetermined width related to the weld bead (BD1, BD2), a repair welding program generation unit (14, 38) configured for generating a repair welding program comprising instructions for: - executing the repair welding on a corresponding position on a welding line in the same manner as a main welding program, in case it is detected that the detected defective portion is located at a position where a distance of the defective portion from the welding line is within the predetermined width, and - executing the repair welding by modifying a part of an operational trajectory to the position of the detected defective portion, thereby directly repairing the defective portion, in case the detected defective portion is farther from the welding line than the predetermined width. an inspection result acquisition unit configured to acquire an appearance inspection result including information about a defective portion of a weld bead (BD1, BD2) of a welded workpiece (Wk) produced by a main welding that is executed by a welding robot; and characterized by a robot control unit configured to instruct the welding robot to execute a repair welding on a position of the defective portion using the appearance inspection result based on a relationship between the position of the defective portion and a predetermined width related to the weld bead (BD1, BD2), a repair welding program generation unit (14, 38) configured for generating a repair welding program comprising instructions for: - executing the repair welding on a corresponding position on a welding line in the same manner as a main welding program, in case it is detected that the detected defective portion is located at a position where a distance of the defective portion from the welding line is within the predetermined width, and - executing the repair welding by modifying a part of an operational trajectory to the position of the detected defective portion, thereby directly repairing the defective portion, in case the detected defective portion is farther from the welding line than the predetermined width. - executing the repair welding on a corresponding position on a welding line in the same manner as a main welding program, in case it is detected that the detected defective portion is located at a position where a distance of the defective portion from the welding line is within the predetermined width, and - executing the repair welding by modifying a part of an operational trajectory to the position of the detected defective portion, thereby directly repairing the defective portion, in case the detected defective portion is farther from the welding line than the predetermined width.