A soft magnetic powder including particles having a composition represented by FexCuaNbb(Si1-yBy)100-x-a-b [provided that a, b, and x are each a number whose unit is at % and satisfy 0.3≤a≤2.0, 2.0≤b≤4.0, and 73.0≤x≤79.5, respectively, and y is a number satisfying f(x)≤y≤0.99, in which f(x)=(4×10−34)x17.56], wherein the particle contains a crystal grain having a grain diameter of 1.0 nm or more and 30.0 nm or less, and includes a Cu segregated portion in which Cu is segregated, the Cu segregated portion is present at a position deeper than 30 nm from a surface of the particle, and a maximum Cu concentration in the Cu segregated portion exceeds 6.0 at %.