A mobile station (UE) comprising: a measurement information storage unit configured to store identification information of a measurement rule, identification information of a measurement object (MO) and association information (MID) for associating the identification information of the measurement rule with the identification information of the measurement object (MO); a measurement unit configured to perform a measurement of a radio quality in a cell using a frequency defined by the identification information of the measurement object stored in the measurement information storage unit; a measurement report transmitter unit configured to transmit a measurement report to the radio base station, when determining that a determination condition defined by the identification information of the measurement rule associated with the identification information of the measurement object is satisfied on the basis of the measurement result of the radio quality; and a handover processor unit configured to perform an inter-frequency handover in response to an instruction from the radio base station, wherein when the inter-frequency handover is performed, the measurement information storage unit is configured to change an association between identification information of a first measurement object (MO#0), corresponding to a cell currently in communication and a first association information (MID#0,MID#1), to an association between identification information of a second measurement object (MO#1), corresponding to a handover destination cell and the first association information; and to change an association between identification information of the second measurement object and a second association information (MID#2), to an association between identification information of the first measurement object (MO#0) and the second association information. a measurement information storage unit configured to store identification information of a measurement rule, identification information of a measurement object (MO) and association information (MID) for associating the identification information of the measurement rule with the identification information of the measurement object (MO); a measurement unit configured to perform a measurement of a radio quality in a cell using a frequency defined by the identification information of the measurement object stored in the measurement information storage unit; a measurement report transmitter unit configured to transmit a measurement report to the radio base station, when determining that a determination condition defined by the identification information of the measurement rule associated with the identification information of the measurement object is satisfied on the basis of the measurement result of the radio quality; and a handover processor unit configured to perform an inter-frequency handover in response to an instruction from the radio base station, wherein when the inter-frequency handover is performed, the measurement information storage unit is configured to change an association between identification information of a first measurement object (MO#0), corresponding to a cell currently in communication and a first association information (MID#0,MID#1), to an association between identification information of a second measurement object (MO#1), corresponding to a handover destination cell and the first association information; and to change an association between identification information of the second measurement object and a second association information (MID#2), to an association between identification information of the first measurement object (MO#0) and the second association information. <EOS>