  We present, for the first time, dark matter halo (DMH) mass measurement of
quasars at $z\sim6$ based on a clustering analysis of 107 quasars.
Spectroscopically identified quasars are homogeneously extracted from the
HSC-SSP wide layer over $891\,\mathrm{deg^2}$. We evaluate the clustering
strength by three different auto-correlation functions: projected correlation
function, angular correlation function, and redshift-space correlation
function. The DMH mass of quasars at $z\sim6$ is evaluated as
$5.0_{-4.0}^{+7.4}\times10^{12}\,h^{-1}M_\odot$ with the bias parameter
$b=20.8\pm8.7$ by the projected correlation function. The other two estimators
agree with these values, though each uncertainty is large. The DMH mass of
quasars is found to be nearly constant $\sim10^{12.5}\,h^{-1}M_\odot$
throughout cosmic time, suggesting that there is a characteristic DMH mass
where quasars are always activated. As a result, quasars appear in the most
massive halos at $z \sim 6$, but in less extreme halos thereafter. The DMH mass
does not appear to exceed the upper limit of $10^{13}\,h^{-1}M_\odot$, which
suggests that most quasars reside in DMHs with
$M_\mathrm{halo}<10^{13}\,h^{-1}M_\odot$ across most of the cosmic time. Our
results supporting a significant increasing bias with redshift are consistent
with the bias evolution model with inefficient AGN feedback at $z\sim6$. The
duty cycle ($f_\mathrm{duty}$) is estimated as $0.019\pm0.008$ by assuming that
DMHs in some mass interval can host a quasar. The average stellar mass is
evaluated from stellar-to-halo mass ratio as
$M_*=6.5_{-5.2}^{+9.6}\times10^{10}\,h^{-1}M_\odot$, which is found to be
consistent with [C II] observational results.
