A mobile communication method according to the present invention includes the steps of: transmitting, from a mobile station (UE) to a radio base station (eNB), a connection re-establishment request signal to re-establish the connection between the radio base station (eNB) and the mobile station (UE), when the mobile station (UE) detects a failure in the connection; and transmitting, from the mobile station (UE) to the radio base station (eNB), a connection reconfiguration completion signal notifying that processing corresponding to a connection reconfiguration signal is completed, when the mobile station (UE) receives the connection reconfiguration signal from the radio base station (eNB), and when the connection reconfiguration signal contains a release request of a data radio bearer which is not established between the mobile station (UE) and the radio base station (eNB).