The atomization technique, which is widely used for producing metallic powders in a large quantity, has been applied to the preparation of amorphous powder of Fe‐Si‐B alloys fairly successfully. The as‐quenched powder consists of noncrystalline and crystalline portions. The fractional volume of the noncrystalline portion increases with decreasing particle size and exceeds 80% for 20‐&mgr; particles. The crystallization temperature of this powder is almost the same as that of the amorphous ribbon with similar composition.