The present invention relates to a method for providing a caller with an arbitrary sound pre-stored in an exchanger that is chosen by a called subscriber instead of a conventional RBT (RingBack Tone). The present method comprises: a first step, conducted by an HLR (Home Location Register) when a location request message is received from a call-originating exchanger because of call connection request to a terminal, of furnishing a call-terminating exchanger with information on whether or not an RBT is to be replaced for the terminal through a routing information request message that is sent to the call-terminating exchanger; and a second step, conducted by the call-terminating exchanger when a trunk connection request from a call-originating exchanger is recognized, of searching for a sound code assigned to the terminal based on the information, and providing a caller with a pre-stored RBT-replacing sound associated with the found sound code as an RBT.