Disclosed is an in-line socket device and its fabricating method. The in-line socket device is covered with a cover shell, and has a movable safety cover connected with one end of the cover shell. The socket device is composed of a base and a base cover, in which one end of the base is open and the other end has three plug sockets. A plurality of axial slots are formed inside the opened end for covering up wires, and terminals are provided within axial slots to make the crimping end and the bared wire to be clipped; accordingly, partial sections of the wires connected with the terminal crimping end can crimp the bared wire through peeling off the PVC cover layer of the section, so that the integrity of wires can be ensured and the problem of power consumption or fallen off from the connection can be prevented.