We have conducted all disk imaging of M33 in 12CO(1-0) using the 45-m telescope at Nobeyama Radio Observatory. We present preliminary results of this project. The spatial resolution of ~ 80 pc is comparable to the size of GMCs. The identified GMCs show wide variety in star forming activity. The variety can be regarded as the difference of their evolutionary stage. We found that Kennicutt-Schmidt law breaks in GMC scale (~ 80 pc), although it is still valid in 1 kpc scale. The correlation between molecular gas fraction, fmol = Σ(H2)/Σ(HI+H2) and gas surface density shows two distinct sequences and shows that fmol tends to be higher near the center. We also made partial mapping 12CO(3-2) with ASTE telescope. These data show that the variation of physical properties of molecular gas are correlated with the GMC evolution and mass. That is, GMCs with more active star formation and more mass tend to have higher fraction of dense gas.

The Magellanic Clouds, consisting of the LMC, the SMC and the Bridge offer an ideal laboratory for studying cluster formation in a lower metal abundance environment at an unrivaled closeness to us among external galaxies. It is known that very young populous clusters like R136 are still being formed in the LMC, where populous clusters include more than 10000 stars tightly gravitationally bound. In this talk, I will present mm and sub-mm CO observations of the Magellanic molecular clouds obtained with NANTEN, SEST, and ASTE at spatial resolutions of 5–50pc. I will then use these CO data to identify the parent cloud cores for populous clusters and discuss the cluster formation by comparing the cloud properties with those of the Milky Way.