A symbol mapping method for repetition coding is disclosed. The symbol mapping method comprises performing repetition coding on codeword to output repeated codeword symbols, and mapping the repeated codeword symbols with subcarriers located in different localized resource blocks. According to the embodiments of the present invention, it is possible to obtain maximum reliability in a receiving side by mapping codeword bits with subcarriers to reduce the number of bits having low reliability when a transmitting side uses repetition coding. Also, it is possible to improve decoding throughput and obtain channel diversity.