The present invention provides a radio base station apparatus that is capable of freely expanding an area, improving the degree of freedom in designing of the area significantly and reducing the equipment investment. The radio base station apparatus includes: a plurality of transmission/reception units which are remotely installed in a service area and to which necessary numbers of carriers and sectors are assigned in accordance with the respective installation areas; a modulation/demodulation unit which can set/modify the soft handover enabled range and modulates/demodulates a signal transmitted/received to/from the transmission reception units; and a selector switch which is connected to the transmission/reception units remotely installed in the service area via cables so as to select connections between the modulation/demodulation unit and the transmission/reception units.