  The physical origin of diffuse Ly$\alpha$ halos (LAHs) around star-forming
galaxies is still a matter of debate. We present the dependence of LAH
luminosity ($L({\rm Ly}\alpha)_H$) on the stellar mass ($M_\star$), $SFR$,
color excess ($E(B-V)_\star$), and dark matter halo mass ($M_{\rm h}$) of the
parent galaxy for $\sim 900$ Ly$\alpha$ emitters (LAEs) at $z\sim2$ divided
into ten subsamples. We calculate $L({\rm Ly}\alpha)_H$ using the stacked
observational relation between $L({\rm Ly}\alpha)_H$ and central Ly$\alpha$
luminosity by Momose et al. (2016), which we find agrees with the average trend
of VLT/MUSE-detected individual LAEs. We find that our LAEs have relatively
high $L({\rm Ly}\alpha)_H$ despite low $M_\star$ and $M_{\rm h}$, and that
$L({\rm Ly}\alpha)_H$ remains almost unchanged with $M_\star$ and perhaps with
$M_{\rm h}$. These results are incompatible with the cold stream (cooling
radiation) scenario and the satellite-galaxy star-formation scenario, because
the former predicts fainter $L({\rm Ly}\alpha)_H$ and both predict steeper
$L({\rm Ly}\alpha)_H$ vs. $M_\star$ slopes. We argue that LAHs are mainly
caused by Ly$\alpha$ photons escaping from the main body and then scattered in
the circum-galactic medium. This argument is supported by LAH observations of
H$\alpha$ emitters (HAEs). When LAHs are taken into account, the Ly$\alpha$
escape fractions of our LAEs are about ten times higher than those of HAEs with
similar $M_\star$ or $E(B-V)_\star$, which may partly arise from lower HI gas
masses implied from lower $M_{\rm h}$ at fixed $M_\star$, or from another
Ly$\alpha$ source in the central part.
