Oxide-coated Fe powder for producing various electromagnetic circuit components requiring high resistivity is provided. The oxide-coated Fe powder is a Mg-containing oxide film-coated iron powder coated with an Mg—Fe—O ternary-based deposition film at least containing (Mg, Fe)O. The (Mg,Fe)O is a crystalline MgO-dissolving wustite. The Mg—Fe—O ternary-based oxide deposition film has a sulfur-enriched layer containing a higher concentration of sulfur than that of central portion of the iron powder, fine crystalline texture having a grain size of 200 nm or less, and the outermost surface is substantially composed of MgO. A composite soft magnetic material using the Mg-containing oxide film-coated iron powder is also provided.