Provided is a Nd-based two-phase separation amorphous alloy by adding an element having a big difference in heat of mixing in a Nd-based alloy with a superior amorphous formability through an inherent characteristic of compositional elements and consideration of thermodynamics, at the time of forming amorphous phase, to thereby enable two-phase separation amorphous alloy during solidification. The Nd-based two-phase separation amorphous alloy is represented as a general equation Nd100-a-b(TM)a(D)b wherein TM is a combination selected from A-B, A-C and B—C when an element group of A consists of Y, Ti, Zr, La, Pr, Gd and Hf, an element group of B consists of Fe and Mn, and an element group of C consists of Co, Ni, Cu and Ag, wherein the content of the element group which constitutes the combination is 5 atomic weight % or greater, and the element selected from each of the element group is at least one element, and the content of one element selected from each of the element group does not exceed 50 atomic weight %, wherein the content of the element group of B is less than that of the element group of C when TM is a B—C combination, and wherein D is at least one selected from the group consisting of Al, B, Si and P, and a and b have the range of 20≦a≦70, 5≦b≦30, and a+b≧40 in terms of atomic weight %.