A method for manufacturing an anisotropic magnet powder characterized in that the method comprises: a high-temperature hydrogenation process of holding an RFeB-based alloy containing a rare earth element (hereinafter referred to as "R"), boron and iron (Fe) as main ingredients in a treating atmosphere under a first predetermined treating pressure (hereinafter referred to as "P1") of which a hydrogen partial pressure ranges from 10 to 100 kPa and at a first predetermined treating temperature (hereinafter referred to as "T1") which ranges from 953 to 1133 K and carrying out a part of a hydrogenation ● disproportionation reaction; a structure stabilization process of holding said RFeB-based alloy after said high-temperature hydrogenation process in a treating atmosphere under a second treating pressure (hereinafter referred to as "P2") of which a hydrogen partial pressure is 10 kPa or more and at a second treating temperature (hereinafter referred to as "T2") which ranges from 1033 to 1213 K, and that at least one of condition T2 > T1 and P2 > P1 is satisfied and completing the hydrogenation ● disproportionation reaction by increasing the reaction rate of the hydrogenation ● disproportionation reaction at an end period thereof; a controlled evacuation process of holding said RFeB-based alloy after said structure stabilization process in a treating atmosphere under a third treating pressure (hereinafter referred to as "P3") of which a hydrogen partial pressure ranges from 0.1 to 10 kPa and at a third treating temperature (hereinafter referred to as "T3") which ranges from 1033 to 1213 K, and a forced evacuation process of removing residual hydrogen from said RFeB-based alloy after said controlled evacuation process, and further comprising a mixing process of mixing a diffusion material containing at least one kind of elements (hereinafter referred to as "R1") consisting of dysprosium (Dy), terbium (Tb), neodymium (Nd), praseodymium (Pr), and lanthanum (La) into said RFeB-based alloy which is obtained after one of said controlled evacuation process and said forced evacuation process, thereby obtaining a mixture powder, and a diffusion heat treatment process of heating said mixture powder, thereby diffusing said R1 on a surface and into an inside of said RFeB-based alloy. a high-temperature hydrogenation process of holding an RFeB-based alloy containing a rare earth element (hereinafter referred to as "R"), boron and iron (Fe) as main ingredients in a treating atmosphere under a first predetermined treating pressure (hereinafter referred to as "P1") of which a hydrogen partial pressure ranges from 10 to 100 kPa and at a first predetermined treating temperature (hereinafter referred to as "T1") which ranges from 953 to 1133 K and carrying out a part of a hydrogenation ● disproportionation reaction; a structure stabilization process of holding said RFeB-based alloy after said high-temperature hydrogenation process in a treating atmosphere under a second treating pressure (hereinafter referred to as "P2") of which a hydrogen partial pressure is 10 kPa or more and at a second treating temperature (hereinafter referred to as "T2") which ranges from 1033 to 1213 K, and that at least one of condition T2 > T1 and P2 > P1 is satisfied and completing the hydrogenation ● disproportionation reaction by increasing the reaction rate of the hydrogenation ● disproportionation reaction at an end period thereof; a controlled evacuation process of holding said RFeB-based alloy after said structure stabilization process in a treating atmosphere under a third treating pressure (hereinafter referred to as "P3") of which a hydrogen partial pressure ranges from 0.1 to 10 kPa and at a third treating temperature (hereinafter referred to as "T3") which ranges from 1033 to 1213 K, and a forced evacuation process of removing residual hydrogen from said RFeB-based alloy after said controlled evacuation process, and further comprising a mixing process of mixing a diffusion material containing at least one kind of elements (hereinafter referred to as "R1") consisting of dysprosium (Dy), terbium (Tb), neodymium (Nd), praseodymium (Pr), and lanthanum (La) into said RFeB-based alloy which is obtained after one of said controlled evacuation process and said forced evacuation process, thereby obtaining a mixture powder, and a diffusion heat treatment process of heating said mixture powder, thereby diffusing said R1 on a surface and into an inside of said RFeB-based alloy.