The invention relates to magnetic parts, such as inductors and antennas, which use metal magnetic powders. The component of complex number of loss magnetic conductivity under GHz band is high. The invention provides soft magnetic metal powder which is characterized in that iron is used as the main component; the average particle size is less than 300 nm; the coercive force (Hc) is 16-119 kA/m (200-1500Oe); the saturation magnetization is more than 90 Am2/kg; by use of a four point probe, it is measured that under 64 MPa (20Kn), 1.0 g of the mentioned metal powder is vertically pressed, and the volume resistivity of a formed molding body is more than 1.0 * 101 Omega*cm; and the loss coefficient under the GHz band of the magnetic parts formed by the soft magnetic parts can be reduced.