A radio network (6) and a radio terminal (4) are configured to, when the radio terminal (4) is using a first cell (10) served by a first radio station (1) as a primary cell and a second cell (20) served by a second radio station (2) as a secondary cell, change the secondary cell form the second cell (20) to a third cell (30) while keeping communication status information regarding the radio terminal (4) on the second cell (20). It is thus, for example, possible to enable a communication service in the secondary cell to be continued after the secondary cell is changed when the radio terminal which is simultaneously using a plurality of cells served by different radio stations changes the secondary cell from a cell of one radio station to a cell of another radio station.