  We study in the framework of R-parity violating supersymmetric theories the
effect of R-parity violation due to the operator L_i L_j \bar{E_k} on the (V-A)
structure of the muon decay. The precisely measured muon decay parameters can
constrain a product of R-parity violating couplings:
|\lambda_{232}\lambda_{131}| < 0.022 at the 90% CL, which is complementary to
the previous limits obtained by the e-\mu universality in \tau decay.
