To improve the secrecy of watermark information which is embedded in a carrier signal, when transmitting the electronic watermark information by embedding it in the carrier signal.

A bandpass splitting section 110 performs bandpass splitting on the carrier signal, and outputs a plurality of bandpass carrier signals which belong to different bands. Modification signal creation sections 131 and 132 generate a modification signal corresponding to each symbol for indicating electronic watermark information. Embedding sections 140 and 150 divide a plurality of bandpass carrier signals into symbol frames of prescribed length, distribute them in a crossing direction between each bandpass, and perform modification process by using a modulation signal of one symbol portion, to a plurality of modulation object elements distributed in a time axis direction. A bandpass synthesis section 170 synthesizes the plurality of processed bandpass carrier signals, and outputs the carrier signal in which the electronic watermark is embedded.

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