  R-parity violating bilinear (soft) terms in the supersymmetric standard model
would be the leading source for nonzero neutrino masses and mixing. We point
out that the mixing between neutralinos (charginos) and neutrinos (charged
leptons) driven by the bilinear terms take factorized forms, which may enable
us to probe the neutrino mixing parameters in a collider. It is then shown that
the Super-Kamiokande data on atmospheric neutrinos require all the baryon
number violating couplings to be substantially suppressed: $\lambda''_{\rm any}
<10^{-9}$.
