In a data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: adding error correction codes for correcting error to said additional information data; embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and transmitting the information data embedded with the repetitive additional information data therein, and comprising, at a receiver side, following steps: receiving the transmitted information data embedded with the repetitive additional information data therein; detecting the repetitive additional information data embedded from said transmitted information data received; determining said additional information data on a basis of a majority rule when receiving said information data; and correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.