Disclosed is an apparatus and a method for performing a cell search in a wireless communication system. A subscriber station calculates the power of subcarriers according to their positions in a preamble signal of a frequency domain and identifies a segment of a cell to which the subscriber station belongs. Then, the subscriber station correlates PN sequences, which correspond to the segment of the cell that has been identified, with the preamble signal of the frequency domain. Therefore, the number of calculations for determining correlation values in a cell search is remarkably reduced.