Rare muon decays at the neutrino factories

New experiments (MEG, MECO) searching for the lepton-flavor violation signal in the muon decay are shown in relation to their ancestor experiments (MEGA, SINDRUM II). It will be also shown tha the neutrino factories and their technologies could be very useful for persuading the rare muon decay experiments further more. As an example, a project PRISM will be explained and the prospect to the rare muon decays and the neutrino factories are shown.