A radio communication system comprising: a macro cell base station for performing radio communication with a mobile communication terminal to relay telephone conversation between mobile communication terminals, the macro cell base station covering an area of a macro cell; a plurality of femtocell base stations installed in a plurality of buildings in the macro cell, each of the femtocell base stations covering an area narrower than the macro cell, and a plurality of sub-femtocell base stations (509, 510) that are installed in the building in addition to the gateway femtocell base station, wherein the plurality of femtocell base stations include a plurality of gateway femtocell base stations; wherein the plurality of gateway femtocell base stations are respectively installed in entrances of the plurality of buildings and cover areas of the respective entrances, wherein each gateway femtocell base station is configured with a gateway identification code that is selected from primary scrambling codes as an identification code, the gateway identification code being common to the plurality of gateway femtocell base stations within the macro cell, wherein the macro cell base station is configured to send system information to the macro cell that includes an adjacent cell list (#1000) and gateway femtocell priority selection setting information, the adjacent cell list (#1000) including an area identification code of each of adjacent macro cells (MC11, MC12) and the gateway identification code set for the gateway femtocell base stations within the macro cell, the gateway femtocell priority selection setting information being information to make the mobile communication terminal preferentially select a gateway femtocell base station when the mobile communication terminal identifies the gateway identification code and detects that it enters the area of the gateway femtocell base station, wherein each of the sub-femtocell base stations (509, 510) is set with a sub-area identification code that is different from the gateway identification code and different from a sub-area identification code of an adjacent femtocell (FC509, FC510) and that is selected from primary scrambling codes, wherein a gateway femtocell which is in the area covered by the macro cell, is configured to send system information comprising an adjacent cell list (#1100) and sub-femtocell priority selection setting information, the adjacent cell list (#1100) including an area identification code of the macro cell and the sub-area identification codes of the adjacent femtocells (FC509, FC510), and the sub-femtocell priority selection setting information being the information for preferentially selecting the sub-femtocell base stations (509, 510). a macro cell base station for performing radio communication with a mobile communication terminal to relay telephone conversation between mobile communication terminals, the macro cell base station covering an area of a macro cell; a plurality of femtocell base stations installed in a plurality of buildings in the macro cell, each of the femtocell base stations covering an area narrower than the macro cell, and a plurality of sub-femtocell base stations (509, 510) that are installed in the building in addition to the gateway femtocell base station, wherein the plurality of femtocell base stations include a plurality of gateway femtocell base stations; wherein the plurality of gateway femtocell base stations are respectively installed in entrances of the plurality of buildings and cover areas of the respective entrances, wherein each gateway femtocell base station is configured with a gateway identification code that is selected from primary scrambling codes as an identification code, the gateway identification code being common to the plurality of gateway femtocell base stations within the macro cell, wherein the macro cell base station is configured to send system information to the macro cell that includes an adjacent cell list (#1000) and gateway femtocell priority selection setting information, the adjacent cell list (#1000) including an area identification code of each of adjacent macro cells (MC11, MC12) and the gateway identification code set for the gateway femtocell base stations within the macro cell, the gateway femtocell priority selection setting information being information to make the mobile communication terminal preferentially select a gateway femtocell base station when the mobile communication terminal identifies the gateway identification code and detects that it enters the area of the gateway femtocell base station, wherein each of the sub-femtocell base stations (509, 510) is set with a sub-area identification code that is different from the gateway identification code and different from a sub-area identification code of an adjacent femtocell (FC509, FC510) and that is selected from primary scrambling codes, wherein a gateway femtocell which is in the area covered by the macro cell, is configured to send system information comprising an adjacent cell list (#1100) and sub-femtocell priority selection setting information, the adjacent cell list (#1100) including an area identification code of the macro cell and the sub-area identification codes of the adjacent femtocells (FC509, FC510), and the sub-femtocell priority selection setting information being the information for preferentially selecting the sub-femtocell base stations (509, 510).