We report Raman scattering spectra for single crystals of overdoped Tl 2Ba 2CuO 6+ δ (Tl-2201) at low temperatures. It was observed that the pair-breaking peaks in A 1g and B 1g spectra radically shift to lower energy with carrier doping. We interpret it as s-wave component mixing into d-wave, although the crystal structure is tetragonal. Since similar phenomena were observed also in YBa 2Cu 3O y and Bi 2Sr 2CaCu 2O z , we conclude that s-wave mixing is a common property for overdoped high- T c superconductors.