To provide a magnet powder with a relatively low Co composition having high saturation magnetic flux density, high coercive force and satisfactory squareness without adopting complicated processes such as Dy diffusion treatment.

The method comprises: a stage A where the fine powder of an (Nd, Pr)-Dy-Fe-Co-B based raw material alloy is prepared; a stage B where the fine powder is heated to occlude hydrogen in the fine powder in the temperature range of 500C under the hydrogen pressure of 100 to 300 kPa, so as to introduce cracks into the grains, and further, temperature is raised in the temperature range of 500C in a vacuum or an inert gas atmosphere, and thereafter, hydrogen is introduced therein at 750 to 1,000C; a stage C where heat treatment is performed at 800 to 900C under the hydrogen pressure of 100 to 300 kPa for 3 to 8 hr; a stage D where heat treatment is performed at 800 to 900C under the hydrogen partial pressure of 10 kPa for 30 min to 8 hr; and a stage E where cooling is performed.