  We simultaneously measured the spatially-resolved CO-to-H$_{2}$ conversion
factor ($\alpha_\mathrm{CO}$) and dust-to-gas ratio (DGR) in nearby galaxies on
a kiloparsec scale. In this study, we used $^{12}$CO($J=1-0$) data obtained by
the Nobeyama 45-m radio telescope with HI and dust mass surface densities. We
obtained the values of global $\alpha_\mathrm{CO}$ and DGR in 22 nearby spiral
galaxies, with averages of $2.66 \pm 1.36\ M_\odot\ \mathrm{pc}^{-2}\
(\mathrm{K\ km\ s^{-1}})^{-1}$ and $0.0052 \pm 0.0026$, respectively.
Furthermore, the radial variations of $\alpha_\mathrm{CO}$ and DGR in four
barred spiral galaxies (IC 342, NGC 3627, NGC 5236, and NGC 6946) were obtained
by dividing them into the inner and outer regions with a boundary of
$0.2R_{25}$, where $R_{25}$ is the isophotal radius at 25 mag arcsec$^{-2}$ in
the $B$ band. The averages of $\alpha_\mathrm{CO}$ and DGR in the inner region
($\leq 0.2R_{25}$) are $0.36 \pm 0.08\ M_\odot\ \mathrm{pc}^{-2}\ (\mathrm{K\
km\ s^{-1}})^{-1}$ and $0.0199 \pm 0.0058$, while those in the outer region ($>
0.2R_{25}$) are $1.49 \pm 0.76\ M_\odot\ \mathrm{pc}^{-2}\ (\mathrm{K\ km\
s^{-1}})^{-1}$ and $0.0084 \pm 0.0037$, respectively. The value of
$\alpha_\mathrm{CO}$ in the outer region is 2.3 to 5.3 times larger than that
of the inner region. When separated into the inner and outer regions, we find
that $\alpha_\mathrm{CO}$ and DGR correlate with the metallicity and the star
formation rate surface density. The value of $\alpha_\mathrm{CO}$ derived in
this study tends to be smaller than those obtained in previous studies for the
Milky Way and nearby star-forming galaxies. This fact can be attributed to our
measurements being biased toward the inner region; we measured
$\alpha_\mathrm{CO}$ at 0.85 and 0.76 times smaller in radius than the previous
works for nearby star-forming galaxies and the Milky Way, respectively.
