The invention relates : en electrode holder comprising an electrically insulating tubular handle, a head member accommodating electrode clamping means provided at one end of said handle and rotatingly supported by an axially outwardly directed bearing surface of said handle, and a cable connector which is axially slidingly mounted within said handle, said connector having a threaded pin shaped portion, which is screwed in a corresponding hole of said head member, a coil spring surrounding said pin shaped portion and engaging a holding surface formed within said handle and directed in a direction turned away from said head portion, characterized in that a radially effective pressure spring means is provided between a sidewall of the cable connector and the opposite unner wall of the handle.