It is an object to provide a sequence allocating method that, while maintaining the number of Zadoff-Chu sequences to compose a sequence group, is configured to make it possible to reduce correlations between different sequential groups. This method includes the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold value (Xth(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether ¦r/N−rb/Nb¦=Xth(m) is satisfied in a step (ST106), including a plurality of Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST107) if the judgment is positive, and allocating the sequence group (rb) to the same cell in a step (ST112).