Sgr B2 is one of the most active star-forming complexes in our Galaxy located ~100 pc from the Galactic center. Whiteoak et al. (1987) found that groups of the OH and H2CO masers and the compact HII regions are aligned in a north-south line, and suggested that star formation there is being triggered by a single large-scale event such as an interaction between molecular clouds. In order to investigate the total molecular cloud distribution and the triggering mechanism of the active massive-star formation in the Sgr B2 region, we mapped it in the 13CO and C18O (J = 1–0) lines with the Nobeyama 45 m telescope in 1988 March and May. In the 13CO line, an area was mapped of 345″ in right ascension and 495″ in declination covering the whole Sgr B2 molecular cloud at a grid spacing of 15″. In the C18O line, more restricted area was observed at 7.5″ or 15″ spacing. The HPBW of the 45 m telescope was 16″ at 110 GHz. Full description of the observations will be given elsewhere (Whiteoak et al. 1997).