A multi-carrier signal transmitter includes a multi-carrier modulation circuit, a power converter, a frequency converter and an interference protection determination circuit, and that the interference protection determination circuit determines a difference in power levels between a higher layer component and a lower layer component of multi-carrier signals in a manner to avoid digital interference. The power converter converts a power level of the multi-carrier signals when necessary based on a data of the determination, and the frequency converter converts a center frequency band of the multi-carrier signals when necessary based on the data of the determination. The digital interference of the hierarchical multi-carrier signals can be prevented.