Provided is a soft magnetic alloy including Fe, as a main component, and including B. Among 80000 pieces of a grid having 1 nm×1 nm×1 nm in a continuous measurement range of the soft magnetic alloy, 4000 pieces of the grid from lower Fe content shows B content variation (σB) of 2.8 or more, and an amorphization ratio X of the soft magnetic alloy of 85% or more.