A mobile communication method, comprising the steps of: in a state where a first radio base station (eNB#1) forwards downlink user data addressed to a mobile station, which is received from a gateway apparatus (S-GW), to a second radio base station (eNB#2) and the second radio base station (eNB#2) transmits the downlink user data addressed to the mobile station to the mobile station, determining, by the second radio base station (eNB#2), to perform handover processing for the mobile station from a cell under the second radio base station (eNB#2) to a cell under a third radio base station (eNB#3); transmitting, by the second radio base station (eNB#2), a handover request signal to the third radio base station (eNB#3), the handover request signal notifying that forwarding of the downlink user data addressed to the mobile station from the first radio base station (eNB#1) to the second radio base station (eNB#2) is ongoing; transmitting, by the third radio base station (eNB#3), a forwarding request signal for the downlink user data addressed to the mobile station, to the first radio base station (eNB#1); in response to the forwarding request signal, switching, by the first radio base station (eNB#1), a forwarding destination of the downlink user data addressed to the mobile station, which is received from the gateway apparatus, from the second radio base station (eNB#2) to the third radio base station (eNB#3); and transmitting, by the third radio base station (eNB#3), the downlink user data addressed to the mobile station, which is received from the first radio base station (eNB#1), to the mobile station. in a state where a first radio base station (eNB#1) forwards downlink user data addressed to a mobile station, which is received from a gateway apparatus (S-GW), to a second radio base station (eNB#2) and the second radio base station (eNB#2) transmits the downlink user data addressed to the mobile station to the mobile station, determining, by the second radio base station (eNB#2), to perform handover processing for the mobile station from a cell under the second radio base station (eNB#2) to a cell under a third radio base station (eNB#3); transmitting, by the second radio base station (eNB#2), a handover request signal to the third radio base station (eNB#3), the handover request signal notifying that forwarding of the downlink user data addressed to the mobile station from the first radio base station (eNB#1) to the second radio base station (eNB#2) is ongoing; transmitting, by the third radio base station (eNB#3), a forwarding request signal for the downlink user data addressed to the mobile station, to the first radio base station (eNB#1); in response to the forwarding request signal, switching, by the first radio base station (eNB#1), a forwarding destination of the downlink user data addressed to the mobile station, which is received from the gateway apparatus, from the second radio base station (eNB#2) to the third radio base station (eNB#3); and transmitting, by the third radio base station (eNB#3), the downlink user data addressed to the mobile station, which is received from the first radio base station (eNB#1), to the mobile station.