A method for producing a powder for a magnetic core, in which an alkoxide film formation step and a silicone resin film formation step are carried out to form an insulation film composed of an alkoxide film and a silicone resin film on the surface of a pure iron powder, wherein the alkoxide film formation step comprises immersing a pure iron powder in an alkoxide-containing solution which is prepared by mixing a Si alkoxide having at least one organic group having a polar group comprising at least one of N, P, S and O atoms and an Al alkoxide with a dehydrated organic solvent, and drying to remove the dehydrated organic solvent, thereby forming an alkoxide film comprising an Al-Si-O type composite oxide on the surface of the pure iron powder; and the silicone resin film formation step comprises immersing the pure iron powder having the alkoxide film formed thereon in a silicone resin-containing solution which is prepared by mixing a silicone resin with an organic solvent, and drying to remove the organic solvent, thereby forming a silicone resin film on the alkoxide film.