A communication terminal apparatus that exhibits a shorter time period required until a start of communication and causes the throughput in the wireless communication system to be less reduced. In this apparatus, when the number, N, of retransmissions notified by a response determining part (107) is zero, a subchannel-to-be-used selecting part (108) selects a subchannel, among others, which exhibits the highest order one of the reception qualities of the subchannels notified by a reception quality determining part (106), and then notifies the selected subchannel to a subchannel allocating part (113). When the notified number, N, of retransmissions is one or more, the response determining part (107) selects a subchannel which exhibits the N-th lower order reception quality than the highest order reception quality, based on the reception qualities of the subchannels notified by the reception quality determining part (106) for a pilot signal received after a transmission of the latest access request signal, and then notifies the selected subchannel to the subchannel allocating part (113).