The present invention provides a mobile communication system, a radio network controller (RNC), and a neighbor cell list filtering method which can control the selection of a frequency to be used at the hard handover performed in a network environment using a plurality of frequency bands and frequencies to reduce the number of activation of the compressed mode operation as much as possible. The RNC produces a filtered neighbor cell list by using information contained in the UE capability indication reported by the user equipment and the use priority data on frequencies designated by the network operator, and neighbor cell information only suitable for the handover is left in the neighbor cell list and notified to the user equipment.