Abstract: A probe pin includes a barrel having an internal space extending from one end to the other end, a plunger provided at the one end of the barrel, a plunger provided at the other end of the barrel, and a coil spring received in the barrel for supporting the plungers elastically. The coil spring includes a central portion having substantially same diameter, a first taper portion adjacent to one end of the central portion and having diameters decreased gradually, and a second taper portion adjacent to the other end of the central portion and having diameters decreased gradually.