The invention provides a carrier frequency offset estimation device and a carrier frequency offset estimation method. The carrier frequency offset estimation device comprises an M-power circuit, a spectrum generating circuit, a peak frequency judging circuit and a frequency offset determining circuit, wherein the M-power circuit carries out an M-power operation for an input signal to generate an M-power operation result; the spectrum generating circuit generates an M-power spectrum for the M-power operation result; the peak frequency judging circuit finds out a peak frequency corresponding to an amplitude peak from the M-power spectrum; and the frequency offset determining circuit determines a carrier frequency offset estimation result according to the peak frequency.