PURPOSE: To give the high saturation magnetization and a sufficent coercive force and to restrain a magnetic characteristic from deteriorating with the passage of time by a method wherein a magnetic metal layer containing cobalt and an oxide layer formed on this layer and containing cobalt are formed on an magnetic oxide powder.

CONSTITUTION: A magnetic metal layer containing cobalt and an oxide layer formed on this layer and containing cobalt are formed on the surface of a magnetic oxide powder. Because the oxidation of the magnetic metal layer is restrained remarkably due to this oxide layer, a deterioration in the high saturation magnetization with the passage of time is reduced and a coercive force is enhanced. As the magnetic oxide powder to form the magnetic metal layer, it is preferable to use the magnetic powder of iron oxide, the magnetic powder of iron oxide containing cobalt, the mag netic powder of barium ferrite, the magnetic powder of chrome oxide or the like. An amount of this magnetic metal layer to be applied is desirably within a range to occupy 5W50wt.% of a total of a ferromagnetic powder. The amount of the oxide layer to be applied is desirably within the range of 1W15wt.% of the total of the ferromagnetic powder. A total content of cobalt in the ferromagnetic powder is desir ably within the range to occupy 6W60wt.% of the total of the ferromagnetic powder.