An objective is to prohibit retransmission of “UE assistance information”. A mobile communication method according to the present invention includes the steps of: transmitting “UE assistance information” to a radio base station (eNB) by a mobile station (UE), the “UE assistance information” prompting the radio base station (eNB) to change a parameter for the mobile station UE used in the radio base station; notifying, by the radio base station (eNB), the mobile station (UE) of a transmission-prohibited period of the “UE assistance information”; and stopping, by the mobile station (UE), retransmission of the “UE assistance information” on the basis of the transmission-prohibited period.