PURPOSE: To easily obtain a sintered compact having high magnetic flux density, low coercive force, and high magnetic permeability by performing the sintering of a green compact of a powder having specific Co, P, and Fe contents and prescribed grain size and the slow cooling of the resulting sintered compact under respectively prescribed conditions.

CONSTITUTION: Powdered Co, and powdered P, and powdered Fe or a powder consisting of an alloy of these metals is blended and formed into a powder consisting of, by weight, 40-60% Co, 0.1-1% P, and the balance Fe and having ≤45μm grain size. A green compact of this powder is sintered at 1100-1450°C. Subsequently, the resulting sintered compact is cooled slowly at 2-50°C/min cooling rate.