This invention addresses the problem of providing an iron base soft magnetic powder for a powder magnetic core that does not use rare metals, that can maintain the electrical insulating properties between the iron powder particles even when subjected to high temperature thermal processing, and that has excellent thermal stability and mechanical strength. This invention also addresses the problem of providing a fabrication method for the iron base soft magnetic powder for the powder magnetic core, and providing the powder magnetic core. In this iron base soft magnetic powder for the powder magnetic core, a phosphatized coating film is formed on the surface of the iron base soft magnetic powder, and a silicon resin coating film is formed on the surface of the phosphatized coating film. The phosphatized coating film contains P, B, Mg, and Al.