Method for managing child resource of group member in wireless communication system and device for same

One embodiment of the present invention discloses a method for handling notification messages for applying a group policy to a notification subscription service in a wireless communication system. The method is carried out by a first M2M device and comprises the steps of: receiving a plurality of notification messages; determining whether a group subscription ID matching a group subscription ID that has been pre-saved on the first M2M device is included in the plurality of notification messages which have been received, wherein the group subscription ID indicates a group policy applied to a subscription service for notification messages for member resources belonging to a specific group; and aggregating notification messages containing the group subscription ID that matches the pre-saved group subscription ID, and applying the group policy corresponding to the group subscription ID to the aggregated notification messages.