A synchronizer ring for use in an automotive speed variator. The ring not only has high strength and toughness but also exhibits high wear resistance, as well as good synchronizing characteristics with respect to a mating member as expressed in terms of friction coefficient. The Cu alloy of which this ring is made has one of the following compositions: (1) 17-40% Zn (all percents are on a weight basis), 2-11% Al and 50-3,000 ppm of oxygen, as well as 0.1-3.5% of at least one element selected from among Ti, Zr and V, 0.003-0.3% Mg and with at least one optional element selected from among Fe, Ni, Co, P, Ca, Mn, Sn, Si and Pb, the balance being Cu and incidental impurities; or (2) 17-40% Zn, 2-11% Al, 0.5-6% Mn, 0.1-2% Si, 0.1-3% of at least one of Fe, Ni and Co, 0.003-0.3% of Mg, and 30-1,000 ppm of oxygen, with at least one optional element selected from among P, Ca, Cr, Pb and Sn, and with the balance being Cu and incidental impurities. In these two compositions, intermetallic compounds and oxides are uniformly dispersed in the matrix.