PURPOSE: To obtain a flux cored wire for welding which has high productivity without disconnection even if high-speed drawing is executed in the stage of a small diameter.

CONSTITUTION: A flux composed of ferromagnetic raw material powder and weakly magnetic raw material powder at a specific compounding ratio is used as the basic prescription for the flux in this process for producing the flux cored wire for welding by supplying the flux to a tubular body during the course of forming metallic band steel to the tubular shape and joining the butt parts of the tubular body by high-frequency welding, then reducing the diameter. The flux is the plural divided prescription fluxes formed by at least bisecting this basic prescription to the first kind divided prescription flux 5 compounded with the weakly magnetic raw material powder and the second kind divided prescription flux 6 compounded with the ferromagnetic raw material powder. The first kind divided prescription flux 5 is supplied to the upper layer side of the tubular body 3 and the second kind divided prescription flux 6 to the lower layer side of the tubular body 3. At least the second kind divided prescription flux 6 is pellets. In addition, iron oxide in the form of superfine powder of a grain size of ≤1.0μm is incorporated into the second kind divided prescription flux 6 at 0.2 to 2.0% of the total weight of the filled flux.