  We search for the decay $B_{s}^{0}\rightarrow\gamma\gamma$ and measure the
branching fraction for $B_{s}^{0}\rightarrow\phi\gamma$ using
121.4~$\textrm{fb}^{-1}$ of data collected at the $\Upsilon(\mathrm{5}S)$
resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$
collider. The $B_{s}^{0}\rightarrow\phi\gamma$ branching fraction is measured
to be $(3.6 \pm 0.5 (\mathrm{stat.}) \pm 0.3 (\mathrm{syst.}) \pm 0.6 (f_{s}))
\times 10^{-5}$, where $f_{s}$ is the fraction of
$B_{s}^{(*)}\bar{B}_{s}^{(*)}$ in $b\bar{b}$ events. Our result is in good
agreement with the theoretical predictions as well as with a recent measurement
from LHCb. We observe no statistically significant signal for the decay
$B_{s}^{0}\rightarrow\gamma\gamma$ and set a $90\%$ confidence-level upper
limit on its branching fraction at $ 3.1 \times 10^{-6}$. This constitutes a
significant improvement over the previous result.
