mass ratio be 30 ppm or less by setting the mass ratio to 30 ppm or less the composite magnetic material having the same characteristics as flat rolled magnetic steel sheets and strips can be obtained a mixing method is not specifically limited but a mixing method such as a mechanical alloying method or a mechano fusion method may be used in addition to a ball mill method materials having a high saturated magnetic flux density and high magnetic permeability such as iron fe iron silicon based fe u2014 si alloy iron nitrogen based fe u2014 n alloy iron nickel based fe u2014 ni alloy iron carbon based fe u2014 c alloy iron boron based fe u2014 b alloy iron cobalt based fe u2014 co alloy iron phosphorous based fe u2014 p alloy iron aluminum based fe u2014 al alloy or iron nickel cobalt based fe u2014 ni u2014 co alloy may be used as metal magnetic materials of the metal magnetic particles it is preferable that an average diameter of the metal magnetic particles ranges from 5 u03bcm to 200 u03bcm setting the average diameter of the metal magnetic particles to 5 u03bcm or more makes oxidation of the metal magnetic particles difficult as compared to the case where the metal magnetic particles have a smaller average diameter and thus inhibits deterioration of the magnetic characteristics thereof further by setting the average diameter of metal magnetic particles to 200 u03bcm or less it.