  We present CO(J=3-2) emission observations with the Atacama Submillimeter
Telescope Experiment (ASTE) toward the 5' x 5' (or 6.6 x 6.6 kpc at the
distance D = 4.5 Mpc) region of the nearby barred spiral galaxy M 83. We
successfully resolved the major structures, i.e., the nuclear starburst region,
bar, and inner spiral arms in CO(J=3-2) emission at a resolution of 22'' (or
480 pc), showing a good spatial coincidence between CO(J=3-2) and 6 cm
continuum emissions. We found a global CO(J=3-2) luminosity L'_CO(3-2) of 5.1 x
10^8 K km s^-1 pc^2 within the observed region. We also found L'_CO(3-2) in the
disk region (0.5 < r < 3.5 kpc) of 4.2 x 10^8 K km s^-1 pc^2, indicating that
CO(J=3-2) emission in the disk region significantly contributes to the global
L'_CO(3-2). From a comparison of a CO(J=3-2) data with CO(J=1-0) intensities
measured with Nobeyama 45-m telescope, we found that the radial profile of
CO(J=3-2)/CO(J=1-0) integrated intensity ratio R_3-2/1-0 is almost unity in the
central region (r < 0.25 kpc), whereas it drops to a constant value, 0.6--0.7,
in the disk region. The radial profile of star formation efficiencies (SFEs),
determined from 6 cm radio continuum and CO(J=1-0) emission, shows the same
trend as that of R_3-2/1-0. At the bar-end (r ~ 2.4 kpc), the amounts of
molecular gas and the massive stars are enhanced when compared with other disk
regions, whereas there is no excess of R_3-2/1-0 and SFE in that region. This
means that a simple summation of the star forming regions at the bar-end and
the disk cannot reproduce the nuclear starburst of M 83, implying that the
spatial variation of the dense gas fraction traced by R_3-2/1-0 governs the
spatial variation of SFE in M 83.
