A multi-carrier signal transmission apparatus transmits a transmission stream including at least preamble information necessary for synchronizing a transmission signal and data information as a multi-carrier signal. A modulator generates a transmission symbol stream by modulating an arrangement of the preamble information and the data information. A symbol expanding portion expands the transmission symbol stream on a frequency axis by generating a complex conjugate value of at least one part of the preamble information symmetrically on the frequency axis.