PCT No. PCT / JP96 / 03118 Sec. 371 Date Jan. 8, 1998 Sec. 102(e) Date Jan. 8, 1998 PCT Filed Oct. 25, 1996 PCT Pub. No. WO97 / 15695 PCT Pub. Date May 1, 1997The copper-based sliding material has improved seizure resistance, even if it is free of Pb, and enables thinning of the overlay. The copper alloy provided consists of from 0.1 to 2% of Ag, from 1 to 10% of Sn, and the balance consisting of Cu and unavoidable impurities and, further said Ag and Sn do not essentially form the secondary phases but are in complete or essentially solid-solution state in the Cu matrix.