A mobile communication system hybridly allows, in a case where an access group consisting of one or more user equipments and one or more base stations is registered, the base station included in the access group to have access in a closed mode from the user equipment included in the same access group and access in an open mode from a user equipment that is not included in the same access group, wherein a communication area of the base station in the open mode is identical to a communication area of the base station in the closed mode. This eliminates a communication area in which the base station serving as an access destination differs between the user equipment in the closed mode and the user equipment in the open mode.