  We present the morphological parameters and global properties of
dust-obscured star formation in typical star-forming galaxies at z=4-6. Among
26 galaxies composed of 20 galaxies observed by the Cycle-8 ALMA Large Program,
CRISTAL, and six galaxies from archival data, we have individually detected
rest-frame 158$\mu$m dust continuum emission from 19 galaxies, nine of which
are reported for the first time. The derived far-infrared luminosities are in
the range $\log_{10} L_{\rm IR}\,[L_{\odot}]=$10.9-12.4, an order of magnitude
lower than previously detected massive dusty star-forming galaxies (DSFGs). The
average relationship between the fraction of dust-obscured star formation
($f_{\rm obs}$) and the stellar mass is consistent with previous results at
z=4-6 in a mass range of $\log_{10} M_{\ast}\,[M_{\odot}]\sim$9.5-11.0 and show
potential evolution from z=6-9. The individual $f_{\rm obs}$ exhibits a
significant diversity, and it shows a correlation with the spatial offset
between the dust and the UV continuum, suggesting the inhomogeneous dust
reddening may cause the source-to-source scatter in $f_{\rm obs}$. The
effective radii of the dust emission are on average $\sim$1.5 kpc and are
$\sim2$ times more extended than the rest-frame UV. The infrared surface
densities of these galaxies ($\Sigma_{\rm
IR}\sim2.0\times10^{10}\,L_{\odot}\,{\rm kpc}^{-2}$) are one order of magnitude
lower than those of DSFGs that host compact central starbursts. On the basis of
the comparable contribution of dust-obscured and dust-unobscured star formation
along with their similar spatial extent, we suggest that typical star-forming
galaxies at z=4-6 form stars throughout the entirety of their disks.
