To provide a method of notching a metal strip in a continuous processing line of the metal strip and the continuous processing line of the metal strip, in which the generation of buckling taking notching in the joined part as the point of origin can be prevented or suppressed.

In this notching equipment 1, by taking a steel strip 5 which is higher in the probability of the generation of buckling between the steel strips 5 to be joined mutually as the reference, notching is punched in the joined part of the mutual steel strips 5 by changing the positions of the upper blade 11 and the guide 12 in the width direction with a traveling hydraulic cylinder 14 on the basis of the kind of steel, thickness and width.