Provided is a method including: receiving a request for one or more first network slices to be accessed by a terminal; receiving terminal subscription information including information about one or more third network slices subscribed as a default; identifying whether one or more second network slices subscribed by the terminal included in the one or more first network slices are an authentication procedure target; when all of the one or more second network slices are the authentication procedure target, adding all of the one or more second network slices to a pending network slice list; performing an authentication procedure based on at least one of the pending network slice list or the one or more third network slices; and determining, based on a result of the authentication procedure, one or more network slices available to the terminal.