Reconfigurable units each include a hardware circuit having one part of a radio procedure function and a reconfigurable circuit having another part of the radio procedure function. An extension interface unit includes a switch circuit having a changeable connection specification to interconnect the reconfigurable units. A memory unit stores logic information for changing logics of the reconfigurable circuits and the connection specification of the switch circuit. A control unit downloads into the memory unit the logic information supplied from outside of the software defined radio. Rewriting the logics of the reconfigurable circuits according to the logic information and switching connection information of the switch circuit makes it possible to realize an optimum logic circuit in compliance with a radio communication to be used. In other words, it is possible to improve the scalability of the radio procedure function of the software defined radio.