An apparatus and method for receiving a ranging signal in an OFDMA mobile communication system are provided. The ranging signal receiving apparatus including, a ranging subchannel extractor for extracting subcarrier values with a ranging signal from a (FFT) signal; a plurality of multipliers for code-demodulating the sub-carrier values by multiplying them by a plurality of ranging codes; each of a plurality of correlators for calculating a plurality of differential correlations in a code-demodulated signal received from a corresponding multiplier; each of a plurality of inverse fast Fourier transform (IFFT) processors for IFFT-processing differential correlations received from a corresponding correlator by mapping the differential correlations to predetermined subcarriers and each of a plurality of maximum value detectors for detecting a maximum value in an IFFT signal received from a corresponding IFFT processor and calculating a timing offset using an IFFT output index having the maximum value.