Arsenic contamination had been found all over Bangladesh in 1993, however, the groundwater flow and the mechanism of arsenic contamination have not been made clear yet. Because the arsenic contamination spreads through the groundwater, it is important to understand the groundwater flow. We performed the field measurement from December 23rd to 25th, 2003 and from May 19th to 21st, 2004. Then we performed the numerical analyses of groundwater flow and arsenic transportation using MODFLOW to grasp the field groundwater condition. As a result of the field measurement, the underground condition of our study area is reductive. Besides, using MODFLOW, we could reproduce the groundwater flow properly and estimate a flux of groundwater drawn from wells, and then, predict the future contamination.