  We present bolometric luminosity ($L_{\rm bol}$) and black hole (BH) mass
($M_{\rm BH}$) estimators based on mid-infrared (MIR) continuum luminosity
(hereafter, $L_{\rm MIR}$) that are measured from infrared (IR) photometric
data. The $L_{\rm MIR}$-based estimators are relatively immune from dust
extinction effects, hence they can be used for dust-obscured quasars. To derive
the $L_{\rm bol}$ and $M_{\rm BH}$ estimators, we use unobscured quasars
selected from the Sloan Digital Sky Survey (SDSS) quasar catalog, which have
wide ranges of $L_{\rm bol}$ ($10^{44.62}$--$10^{46.16}$\,$\rm erg\,s^{-1}$)
and $M_{\rm BH}$ ($10^{7.14}$--$10^{9.69}$\,$M_{\odot}$). We find empirical
relations between (i) continuum luminosity at 5100\,$\rm{\AA{}}$ (hereafter,
L5100) and $L_{\rm MIR}$; (ii) $L_{\rm bol}$ and $L_{\rm MIR}$. Using these
relations, we derive the $L_{\rm MIR}$-based $L_{\rm bol}$ and $M_{\rm BH}$
estimators. We find that our estimators allow the determination of $L_{\rm
bol}$ and $M_{\rm BH}$ at an accuracy of $\sim$0.2\,dex against the fiducial
estimates based on the optical properties of the unobscured quasars. We apply
the $L_{\rm MIR}$-based estimators to SDSS quasars at $z \lesssim 0.5$
including obscured ones. The ratios of $L_{\rm bol}$ from the $L_{\rm
MIR}$-based estimators to those from the optical luminosity-based estimators
become larger with the amount of the dust extinction, and a non-negligible
fraction ($\sim$15\,\%) of the SDSS quasars exhibits ratios greater than 1.5.
This result suggests that dust extinction can significantly affect physical
parameter derivations even for SDSS quasars, and that dust extinction needs to
be carefully taken into account when deriving quasar properties.
