The present invention is to provide powder made of iron-based metallic glass, the corrosion resistance of which is improved over the conventional powder made of iron-based metallic glass. The basic composition includes a group of iron-based metallic elements that predominantly has Fe, a group of metalloid elements that consists of Si, B, P, and C, and a little amount of a group of elements for improving the degree of supercooling that consists of either or both of Nb and Mo. The powder made of the iron-based metallic glass is obtained by adding to the basic composition an element for improving the corrosion resistance. The obtained powder made of the iron-based metallic glass has an excellent corrosion resistance, an excellent magnetic property, and an excellent insulating property.