  We present aperture synthesis high-resolution (~ 7" x 3") observations in
CO(J=1-0) line, HCN(J=1-0) line, and 95 GHz continuum emission toward the
central (~ 1.5 kpc) region of the nearby barred spiral galaxy M 83 with the
Nobeyama Millimeter Array. Our high-resolution CO(J=1-0) mosaic map depicts the
presence of molecular ridges along the leading sides of the stellar bar and
nuclear twin peak structure. On the other hand, we found the distribution of
the HCN(J=1-0) line emission which traces dense molecular gas (nH2 > a few x
10^4 cm^-3) shows nuclear single peak structure and coincides well with that of
the 95 GHz continuum emission which traces massive starburst. The peaks of the
HCN(J=1-0) line and the 95 GHz continuum emission are not spatially coincident
with the optical starburst regions traced by the HST V-band image. This
suggests the existence of deeply buried ongoing starburst due to strong
extinction (A_v ~ 5 mag) near the peaks of the HCN(J=1-0) line and the 95 GHz
continuum emission. We found that the HCN(J=1-0)/CO(J=1-0) intensity ratio
R_HCN/CO correlates well with extinction-corrected SFE in the central region of
M 83 at a resolution of 7.5" (~ 160 pc). This suggests that SFE is controlled
by dense gas fraction traced by R_HCN/CO even on a Giant Molecular cloud
Association (GMA) scale. Moreover, the correlation between R_HCN/CO and the SFE
in the central region of M 83 seems to be almost coincident with that of the
Gao & Solomon (2004a) sample. This suggests that the correlation between
R_HCN/CO and the SFE on a GMA (~ 160 pc) scale found in M 83 is the origin of
the global correlation on a few kpc scale shown by Gao & Solomon (2004a).
