The present disclosure relates to a communication technique for converging an IoT technology with a 5G communication system for supporting a higher data transmission rate beyond a 4G system, and a system therefor. The present disclosure may be applied to an intelligent service (for example, a smart home, a smart building, a smart city, a smart car or connected car, healthcare, digital education, retail business, a security and safety related service, or the like) on the basis of a 5G communication technology and an IoT related technology. Disclosed are an apparatus for transmitting data through at least one of a first path and a second path, and a method therefor. A method for an apparatus according to an embodiment of the present invention may comprise the steps of: identifying the size of data transmittable through a first path during a reference time for a second path; comparing the identified data size with the buffer size of a reception device; and determining a transmission mode on the basis of a result of the comparison, and transmitting the data to the reception device according to the determined transmission mode.