An offset estimation apparatus for a multi-carrier communication system is provided. The offset estimation apparatus includes an FFT unit configured to transform a reception signal and to generate multiple symbols, a conjugate multiplier configured to receive and conjugate multiply two consecutive symbols corresponding to predetermined subcarrier indices to generate multiple correlating complex numbers, a powering unit configured to raise the correlating complex numbers by a received exponent to generate multiple powered correlating complex numbers, and a calculation unit configured to estimate a frequency offset according to the powered correlating complex numbers.