A method for transmitting, by a first mobility management entity (MME), a group message in group units, to which a plurality of terminals belong, in a wireless communication system according to one embodiment of the present invention may comprise the steps of: receiving a group message request message requesting for transmission of the group message, wherein the group message request message includes a group identifier (ID) of a group to receive the group message, delivery contents to be transmitted to the group, and validity time which buffers the delivery contents; detecting a first terminal connected to the first MME within the validity time; confirming whether the group ID of the detected first terminal is identical to the group ID of the group message request message; and, if the two group IDs are identical, transmitting the delivery contents to the first terminal.