  We report the X-ray population study in the giant molecular cloud Sagittarius
B2 (SgrB2). More than a dozen of X-ray cloud members (and candidates) are
discovered with Chandra. Two bright X-ray sources are located near Sgr B2 Main,
the most copious complex of the ultra compact HII sources. The X-ray spectra
are fitted with a thin thermal plasma model of 5-10 keV temperature. The
intrinsic luminosity after correcting the absorption of 5 x 10^23 H/cm^2 is
about 10^33 erg/s. Although these two X-ray sources are attributable to young
stellar objects (YSOs) in the same HII complex, they are in sharp contrast; one
at the center of the HII complex exhibits strong K-shell transition lines of
iron, while the other near the east has only weak lines. The other HII
complexes, SgrB2 North and South, also show hard and highly absorbed X-ray
emissions due possibly to the star formation activity. The composite X-ray
spectrum of the other cloud member X-ray sources is fitted with a thin thermal
plasma of about 10-keV temperature with the hydrogen column density (N_H) of
1.3 x 10^23 H/cm^2, and the individual X-ray luminosity of a few times of
10^31-32$ erg/s. These are likely to be a single or cluster of YSO(s), but
neither radio nor infrared counterpart is found. An alternative scenario of
isolated white dwarfs powered by the Bondi-Hoyle accretion from the dense cloud
gas is also discussed. The X-ray spectra exhibit an additional 6.4-keV line of
neutral or low-ionization irons, which indicates that the environment gas is
concentrated near at the sources.
