A macro base station MeNB in a mobile communication system that supports a carrier aggregation technology defined in a 3GPP standard, communicates with a pico base station PeNB #1 via an X2 interface. The macro base station MeNB transmits information to the pico base station PeNB the information being used when the pico base station PeNB determines a component carrier requested to be limitedly used by the macro base station MeNB or a component carrier requested to be released from use limitation by the macro base station MeNB.