A magnetic powder for magnetic recording medium comprises acicular particles constituted primarily of Fe, wherein the powder contains Co in an amount such that the Co/Fe ratio is 50 at. % or less and the Co is contained in a manner such that the surface portion has a higher concentration than the core portion of the particles, and upon subjecting the magnetic powder for magnetic recording medium to TG measurement, the powder exhibits at least two oxidation starting points: a low-temperature side oxidation starting point and a high-temperature side oxidation starting point. The magnetic powder achieves improved resistance to oxidation without sacrificing magnetic characteristics.