A soft magnetic ribbon that especially in a relatively low magnetic field region of 500 A/m or less, is high in the squareness of magnetic flux density-magnetization curve. There is disclosed a soft magnetic ribbon of 100 μm or less thickness comprising a parent phase structure in which by volume ratio, 30% or more of crystal grains of 60 nm or less (not including 0) crystal grain diameter are dispersed in an amorphous phase and comprising an amorphous layer disposed on the surface side of the parent phase structure. Preferably, the soft magnetic ribbon is represented by the composition formula Fe100-x-yCuxXy (wherein X is at least one element selected from among B, Si, S, C, P, Al, Ge, Ga and Be), in which the atomic percents (%) satisfy the relationships 0