  A sensitive observation of the CO (J=1-0) molecular line emission in the host
galaxy of GRB 030329 (z =0.1685) has been performed using the Nobeyama
Millimeter Array in order to detect molecular gas and hidden star formation. No
sign of CO emission was detected, which invalidates our previous report on the
presence of molecular gas. The 3sigma upperlimit on the CO line luminosity
(L'_CO) of the host galaxy is 6.9 x 10^8 K km s^-1 pc^2. The lowerlimit of the
host galaxy's metallicity is estimated to be 12+log(O/H) ~ 7.9, which yields a
CO line luminosity to H_2 conversion factor of alpha_CO = 40 Msun (K km s^-1
pc^2)^-1. Assuming this alpha_CO factor, the 3sigma upperlimit on the molecular
gas mass of the host galaxy is 2.8 x 10^10 Msun. Based on the Schmidt law, the
3sigma upperlimit of the total star formation rate (SFR) of the host galaxy is
estimated to be 38 Msun yr^-1. These results independently confirm the
inferences of previous observations in the optical, submillimeter, and X-ray
band, which regard this host galaxy as a compact dwarf galaxy, and not a
massive, aggressively star forming galaxy.
