An Fe-based soft magnetic alloy includes: Fe; and a component R, wherein the component R contains at least one of P, C, B, and Si, there is a temperature difference of equal to or greater than 20° C. between a precipitation temperature of an α-Fe crystal phase and a precipitation temperature of an Fe compound, the Fe-based soft magnetic alloy is formed of a mixed-phase structure in which an amorphous phase and the α-Fe crystal phase are mixed, and a diameter of a crystallite of the α-Fe crystal phase is equal to or smaller than 50 nm, and a volume fraction of the α-Fe crystal phase to the total is equal to or lower than 40%. In addition, the composition formula is represented by Fe100−x−uJxRu, a component J contains at least one of Cr, Co, Ni, and Nb, and 0 at %≦x≦6 at %, 17 at %≦u≦25 at %, and 17 at %≦x+u≦27.1 at % are satisfied.