A wireless communication apparatus wherein the performance can be prevented from degrading due to the affection of a frequency offset, while the sequence length of Zadoff-Chu sequence (ZC sequence) being kept long. In this wireless communication apparatus, a ZC sequence generating part (11) generates a ZC sequence corresponding to a preamble number that is selected at random and then inputted; a randomizing part (12) randomizes the ZC sequence; a preamble generating part (13) generates a preamble from the randomized ZC sequence; and a radio transmitting part (14) transmits, via an antenna (15), the preamble after subjecting it to predetermined radio transmission processes, such as a D/A conversion, an up-conversion and so on. For example, the randomizing part (12) multiplies the ZC sequence by a PN sequence so as to randomize the ZC sequence.