To provide method for forming a Ti-Ni alloy film which is heretofore difficult with the conventional plating method and which has high quality at a low cost by a plating method using a plating bath of an aqueous solution which is easy to handle and is excellent in productivity without requiring costly equipment and intricate operation.

The method for forming the Ti-Ni alloy film by the plating method of easily forming the homogeneous and high-quality Ti-Ni alloy film by incorporating metal Ti particles into the plating bath, and performing the plating to form the Ni plating film containing the metal Ti particles, then alloying the plating film by heating is provided.