A method for producing a filled skutterudite-based alloy includes the steps of melting alloy raw material that includes a rare earth metal R that is at least one species selected from among La, Ce, Pr, Nd, Sm, Eu and Yb, a transition metal T that is at least one species selected from among Fe, Co, Ni, Os, Ru, Pd, Pt and Ag, and metallic antimony Sb to form a melt; and rapidly quenching the melt through strip casting to form a solidified product that is the filled skutterudite-based alloy advantageously usable for a thermoelectric element.