The thermo-magnetic-treated anisotropic permanent magnet alloy of the present invention consists essentially of, by weight, 17 to 45% chromium, 3 to 14.5% cobalt, 0.2 to 5% silicon and balance substantially iron, preferably 23 to 35% chromium, 7 to 14.5% of cobalt, 0.3 to 3% silicon and balance substantially iron and has a residual magnetic flux density of 7000 Gauss or more and a coersive force of 300 Oersted or more. In order to obtain the alloy, an alloy having the above identified composition is initially aged at a temperature of 570.degree. C to 670.degree. C for a period of 10 minutes to 5 hours in a magnetic field and secondarily aged at a temperature within 200.degree. C below the thermo-magnetic treatment temperature for a period of 30 minutes to 50 hours.