  We report on muon spin rotation studies of the noncentrosymmetric heavy
fermion antiferromagnet CeRhSi$_3$. A drastic and monotonic suppression of the
internal fields, at the lowest measured temperature, was observed upon an
increase of external pressure. Our data suggest that the ordered moments are
gradually quenched with increasing pressure, in a manner different from the
pressure dependence of the N\'eel temperature. At $\unit{23.6}{kbar}$, the
ordered magnetic moments are fully suppressed via a second-order phase
transition, and $T_{\rm{N}}$ is zero. Thus, we directly observed the quantum
critical point at $\unit{23.6}{kbar}$ hidden inside the superconducting phase
of CeRhSi$_3$.
