To provide a technology capable of reducing a processing load on a base station controller and restraining a traffic quantity within a mobile communication system. A base station apparatus connected to a base station controller has a first establishing unit establishing a first logic communication path between the base station apparatus and the base station controller; a second establishing unit establishing a second logic communication path between the base station apparatus and another base station apparatus; and a forwarding unit forwarding data, transmitted and received with the another base station apparatus and the base station controller serving as terminal points, as data of another base station apparatus via the first logic communication path and the second logic communication path.