The present disclosure in an aspect provides a method of managing mobility of a UE in a wireless communication system, including 1) determining in an RRC inactive state (an RRC inactive mode), whether to change a serving cell that is currently attached, 2) when determining to change the serving cell, receiving a system information from a target cell, and checking, based on the system information, whether a base station that controls the serving cell is identical to or different from a base station that controls the target cell, and 3) depending on identity or difference between the base station that controls the target cell and the base station that controls the serving cell, performing i) releasing an RRC-connection to thereby transition into an idle state, or ii) a cell change procedure to the target cell.