To provide a method for forming wavy wire capable of securely forming a wire into a prescribed wavy shape with a simple structure, and to provide a device therefor.

First projecting parts 30 arranged to the length direction of a wire WA at intervals each other are abutted from one side direction to the wire WA, further, second projecting parts 40 arranged to the length direction of the wire WA alternately with each first projecting part 30 are abutted against the wire WA from the other side direction, thus the wire WA is alternately bent to one side direction and the other side direction, respectively, further, since the WA is carried to the length direction by the rotation of respective belts 10, 20, the wire WA fed from a material roll R can be continuously formed into a wavy shape, and also, the width dimensions of the wire WA formed into a wavy shape can be easily and securely controlled by changing the positions of the respective projecting parts 30, 40.