  We search for the $B^0\to p\bar{\Sigma}^0\pi^-$ decay with $\bar{\Sigma}^0
\to \bar{\Lambda}\gamma$, where the $\gamma$ is not measured, using a data
sample corresponding to an integrated luminosity of 711 $\rm{fb^{-1}}$ which
contains 772 $\times$ $10^{6}$ $B\bar{B}$ pairs, collected around the
$\Upsilon$(4S) resonance with the Belle detector at the KEKB asymmetric-energy
$e^{+}e^{-}$ collider. We measure for the first time the $B^0\to
p\bar{\Sigma}^0\pi^-$ branching fraction to be $\mathcal{B}(B^0 \to p
\bar\Sigma^0 \pi^-) = (1.17^{+0.43}_{-0.40}(\text{stat})\pm 0.07(\text{syst}))
\times 10^{-6}$ with a significance of $3.0\sigma$. We simultaneously measure
the branching fraction for the related channel $B^{0}\to p\bar{\Lambda}\pi^{-}$
with much improved precision.
