Provided are an apparatus and method for transmitting multi-carriers to provide a high-quality service to multicast-based service subscriber terminals. The method includes: mapping first data for providing the multicast service, and second data different from the first data, to different antennas; converting the first mapped data into a first Intermediate Frequency (IF) signal and the second mapped data into a second IF signal; converting the first IF signal into a first RF signal having a carrier frequency, and deciding a power intensity of the first RF signal so that the first RF signal is transmitted over the entire coverage region of the base station; and converting the second IF signal into a second RF signal having the other carrier frequency, and deciding a power intensity of the second RF signal so that the second RF signal is transmitted over a predetermined region around the base station.