A timing adjustment method in a mobile communication system having a user equipment and a base station, that performs transmission processing based on transmission timing adjustment information in the user equipment and allocates a plurality of parameters related to a physical uplink control channel (PUCCH) resource used for transmission processing, between the user equipment and the base station. Additionally, if a valid term of first transmission timing adjustment information expires before transmission processing of a signal including identification information of the user equipment is performed during connection processing while the user equipment is performing the connection processing to the base station based on the first transmission timing adjustment information, aborting the connection processing and releasing at least one of the allocated plurality of parameters related to the PUCCH resource.