Neutrinoless tau-lepton decays into either three leptons (tau- --> l(1)(-)l(2)l(3)) or one lepton and one K-S(0) meson(tau- --> l(-)K(S)(0)) where lepton means either an electron or muon, have been searched for using 48.6 fb(-1) of data collected with the Belle detector at the KEKB e(+)e(-) collider. No evidence for candidate decays are found in any channel. Therefore we set 90% confidence level upper limits on the branching fraction for 8 different decay modes. These limits are more stringent than those set previously and reach to the 10(-7) level.