PURPOSE: To prevent the trouble at the steel strip side equipment material side at the time of welding and to reduce the generation of weld zone marks at the time of rolling by carrying out side processing to equalize the width of the rear end of a preceding steel strip and the tip of a succeeding steel strip before the preceding and succeeding steel strips are introduced into a seam welding machine.

CONSTITUTION: In continuous steel strip manufacturing equipment, a steel strip 6 rewound from a payoff reel 1 is executed stress relieving through a leveler 2 and a steel strip end is cut off by a shear 3. In a next notcher 4, the side of the preceding coil rear end 7 or the succeeding coil tip 8 or both of those are notched to equalize the width of the preceding and succeeding steel strips and then, these are introduced into welding work of the seam welding machine 5.