The present specification relates to a method by which a first terminal transmits uplink (UL) data in a wireless communication system supporting a low latency service, the method comprising the steps of: transmitting, to a base station, an urgent signal (US) for notifying of the occurrence of an event related to an emergency; receiving a response to the US from the base station through a physical HARQ indication channel (PHICH) resource; and transmitting, to the base station, urgent data including specific information related to the occurred event on the basis of the received response, wherein the PHICH resource is mapped with a transmission resource of the US.