A electric contact pin which can certainly contact a plunger with a contact spring and ensure smooth operation (vertical motion) of the plunger. The present invention can execute electrical tests of the electrical parts accurately. The electric contact pin according to the present invention contacts an eccentrical portion of an open coil portion provided for the contact spring capable of easily deforming in a radial direction with a conductive portion of the plunger. Consequently, the conductive portion of the plunger is elastically pinched between the eccentrical portion of the open coil portion and the closed coil portion. The eccentrical portion of the open coil portion and the closed coil portion are contact with the conductive portion of the plunger at any time.