PROBLEM TO BE SOLVED: To obtain a high-purity tin or a tin alloy having low α-ray dose for a solder material used for s semiconductor device requiring high density and high volume, and to provide a process for producing the high-purity tin. SOLUTION: The high-purity tin or tin alloy is characterized in that contents of U and Th are each 5 ppb or less, contents of Pb and Bi are each 1 ppm or less and purity is 5N or higher (provided that the gas components of O, C, N, H, S and P are excluded) and in that the α-ray count of the high purity tin having the cast structure is reduced to 0.001 cph/cm 2 or less. The process for producing the tin alloy and the high purity tin comprises: leaching the tin as the raw material with acid; using this leached solution as an electrolytic solution to suspend an absorbing material for impurity in this electrolytic solution; and performing electro-refining by using a raw material Sn anode. COPYRIGHT: (C)2010,JPO&INPIT