Abstract: The present invention provides an audio signal adapter, which includes a plug, a metal jack and a plastic set. The plug and the metal jack are electronically connected to two terminals of a cable respectively. The plug may be an earphone plug or a microphone plug. Correspondingly, the metal jack may be an earphone jack or a microphone jack. The plastic set includes a thin and flat base. The top central section of the base extends upward in order to form a socket. A slot is defined in the front of the socket. The metal jack is embedded in the slot. With the design of the thin and flat base, the plastic set can be firmly and conveniently fixed to the external ornament of the bag by typical assembling method such as sewing and sticking.