  Using the AKARI, Wide-field Infrared Survey Explorer (WISE), Infrared
Astronomical Satellite (IRAS), Sloan Digital Sky Survey (SDSS) and Hubble Space
Telescope (HST) data, we investigated the relation of polycyclic aromatic
hydrocarbon (PAH) mass ($M_{\rm PAH}$), very small grain mass ($M_{\rm VSG}$),
big grain mass ($M_{\rm BG}$) and stellar mass ($M_{\rm star}$) with galaxy
merger for 55 star-forming galaxies at redshift $z<0.2$. Using the SDSS image
at $z<0.1$ and the HST image at $z>0.1$, we divided the galaxies into merger
galaxies and non-merger galaxies with the morphological parameter asymmetry
$A$, and quantified merging stages of galaxies based on the morphological
indicators, the second-order momentum of the brightest 20$\%$ region $M_{20}$
and the Gini coefficient. We find that $M_{\rm PAH}/M_{\rm BG}$ of merger
galaxies tend to be lower than that of non-merger galaxies and there are no
systematic differences of $M_{\rm VSG}/M_{\rm BG}$ and $M_{\rm BG}/M_{\rm
star}$ between merger galaxies and non-merger galaxies. We find that galaxies
with very low $M_{\rm PAH}/M_{\rm BG}$ seem to be merger galaxies at late
stages. These results suggest that PAHs are partly destroyed at late stages of
merging processes. Furthermore, we investigated $M_{\rm PAH}/M_{\rm BG}$
variations in radiation field intensity strength $G_0$ and the emission line
ratio of $[{\rm O\,{\scriptsize I}}]\lambda 6300/{\rm H}\alpha$ which is a
shock tracer for merger galaxies and find that $M_{\rm PAH}/M_{\rm BG}$
decreases with increasing both $G_0$ and $[{\rm O\,{\scriptsize I}}]/{\rm
H}\alpha$. PAH destruction is likely to be caused by two processes; strong
radiation fields and large-scale shocks during merging processes of galaxies.
