We investigate the pattern of job mobility across regions using the big data of National Pension Service. Our results from Logit regressions indicate that the probability of interregional job mobility is significantly higher for the young-aged, male, high income earners or those who employed in large or aged establishments. Also, the probability is higher in service than manufacturing sector, and in regions other than Seoul. Our findings imply that interregional job mobility exacerbates population decrease and brain drain in local area. To alleviate the population imbalance across regions, more decent jobs should be provided in local area.