  We report the measurement of branching fractions and $CP$-violation
asymmetries in $B\to \phi \phi K$ decays based on a $711\,{\rm fb}^{-1}$ data
sample containing $772\times 10^6$ $B\bar{B}$ events. The data were recorded at
the $\Upsilon (4S)$ resonance with the Belle detector at the KEKB
asymmetric-energy $e^+ e^-$ collider. For $B^+ \to \phi \phi K^+$, the
branching fraction and $CP$-violation asymmetry measured below the $\eta_{c}$
threshold ($m_{\phi\phi}<2.85\,{\rm GeV}/c^2$) are
$[3.43^{\,+\,0.48}_{\,-\,0.46}({\rm stat})\pm 0.22({\rm syst})] \times10^{-6}$
and $-0.02\pm0.11({\rm stat})\pm0.01({\rm syst})$, respectively. Similarly, the
branching fraction obtained for $B^0 \to\phi\phi K^0$ below the $\eta_{c}$
threshold is $[3.02^{\,+\,0.75}_{\,-\,0.66} ({\rm stat})\pm \,0.20({\rm
syst})]\times10^{-6}$. We also measure the $CP$-violation asymmetry for $B^+
\to\phi\phi K^+$ within the $\eta_{c}$ region ($m_{\phi\phi}\in
[2.94,3.02]\,{\rm GeV}/c^2$) to be $+0.12\pm0.12({\rm stat})\pm0.01({\rm
syst})$.
