To prevent a substance having high electric resistance from adhering to the contact part of a contact pin, by applying specific plating to the contact part of the contact pin of an IC socket, and to the mounting connection part of the contact pin respectively.

In an IC socket, wherein many contact pins 1 are plantedly provided on a main body 2, for electrically connecting between a lead 3a and a circuit board, by mounting an IC package 3 applied soldering plating to a lead 3a; the following means are adopted. That is, at least the surface of the contact part 1a with the lead 3a of a contact pin 1 is bad in solder wettability, also is applied plating by a substance having low electric resistance, and moreover gold plating is applied on at lest the surface of a soldering connecting part 1b of the contact pin 1 when the contact pin 1 is mounted. As plating material applied to the surface of the contact part 1a of the contact pin, for example, Ag-C, Au-Ni, Ni-B, and Pd-P are cited.