PURPOSE: To efficiently manufacture alloy powder having excellent magnetic characteristic by pulverizing alloy containing Fe, Co, Ga, (Si, Al, Ge, B, C, P) as essential components with atomizing method.

CONSTITUTION: Molten metal having composition composed of 0.5-10at% Ga and ≤6% the total of one or more kinds of Nb, Zr, Hf, Ta, Mo, W, Ti, 3-18% the total of one or more kinds of Si, Ge, Al and 3-20% the total of one or more kinds of B, C, P and the balance Fe with inevitable impurities, is prepared. This molten metal is made to powdery solid with the atomizing method to make the atomized alloy powder composed of ≥about 50vol.% amorphous material. Further, a part of Fe content may be replaced to one or more kinds of ≤5% Ni, ≤5% Mn, Cr, V and ≤30% Co. This alloy powder has excellent magnetic characteristic of coercive force, etc., and can be used to saturable reactor for switch electric source, magnetic core material of magnetic head, etc., magnetic shield material, etc.