  We carried out 2.5-dimensional resistive MHD simulations to study the
formation mechanism of molecular loops observed by Fukui et al. (2006) at
Galactic central region. Since it is hard to form molecular loops by uplifting
dense molecular gas, we study the formation mechanism of molecular gas in
rising magnetic arcades. This model is based on the in-situ formation model of
solar prominences, in which prominences are formed by cooling instability in
helical magnetic flux ropes formed by imposing converging and shearing motion
at footpoints of the magnetic arch anchored to the solar surface. We extended
this model to Galactic center scale (a few hundreds pc). Numerical results
indicate that magnetic reconnection taking place in the current sheet formed
inside the rising magnetic arcade creates dense blobs confined by the rising
helical magnetic flux ropes. Thermal instability taking place in the flux ropes
forms dense molecular filaments floating at high Galactic latitude. The mass of
the filament increases with time, and can exceed 10^5 solar mass.
