A magnetic sensing element exhibiting a large .DELTA.RA is provided, in which a free magnetic layer has a small coercive force Hc and a small magnetostriction constant .lamda.s. The free magnetic layer includes a Co.sub.2MnZ alloy layer (where Z may represent at least one element selected from the group consisting of Al, Sn, In, Sb, Ga, Si, Ge, Pb, and Zn) and a (Ni.sub.aFe.sub.100-a).sub.bX.sub.100-b alloy layer (where X may represent at least one element selected from the group consisting of Cu, Au, Ag, Zn, Mn, Al, Cd, Zr, and Hf, a may represent a composition ratio satisfying 80