Provided are a method and an apparatus for competition-based transmitting of uplink data in a wireless communication system to which a non-orthogonal multiple access scheme is applied. Particularly, a UE receives, from a base station, information relating to a contention zone. The information relating to the contention zone includes predefined contention zone patterns and predefined terminal classes. The terminal selects a terminal class for the terminal from among the predefined terminal classes. The terminal selects a contention zone pattern for the terminal from among the predefined contention zone patterns on the basis of the selected terminal class. The uplink data is transmitted to the base station through a plurality of contention zones included in the selected contention zone pattern.