The present disclosure relates to a communication technique for combining IoT technology with a 5G communication system for supporting a higher data transmission rate than 4G communication systems and to a system therefor. The present disclosure may be applied to intelligent services, such as smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail businesses, and security-and safety-related services on the basis of 5G communication technology and IoT-related technology. Disclosed are a method and apparatus for retransmitting only the code block, in a transport block, requiring retransmission and not the entire transport block if retransmission of the initially transmitted transport block is necessary.