A method is provided for tightening up threaded members with proper tightening torque free of unequivalent tightening. In tightening a plurality of threaded members by drive means, the amount of tightening and tightening torque of each threaded member are detected as the members are progressively tightened, and when the tightening amount of each member has reached a value within a specified range, the difference in tightenting torque between the threaded members is checked as to whether it is within a predetermined range. <IMAGE>
