  We present a comparative study of CO and polycyclic aromatic hydrocarbon
(PAH) emission toward a region including the massive star-forming regions of
NGC 6334 and NGC 6357. We use the NANTEN $^{12}$CO($J$ = 1--0) data and the
$AKARI$ 9 $\mu$m All-Sky diffuse map in order to evaluate the calibration
accuracy of the $AKARI$ data. We confirm that the overall CO distribution shows
a good spatial correspondence with the PAH emission, and their intensities
exhibit a good power-law correlation with a spatial resolution down to 4$'$
over the region of 10$^\circ$$\times$10$^\circ$. We also reveal poorer
correlation for small scale structures between the two quantities toward NGC
6357, due to strong UV radiation from local sources. Larger scatter in the
correlation toward NGC 6357 indicates higher ionization degree and/or PAH
excitation than that of NGC 6334.
