An unlubricated bearing structure for supporting a rocking arm of an IC socket includes an arm support as an operating member that supports the rocking arm, a support shaft, made of metal, fitted and fixed to the arm support, and a cylindrical bush, made of metal, mounted to the support shaft so that the cylindrical bush is fitted into a bearing hole formed to the rocking arm. The support shaft, the cylindrical bush and the rocking arm are arranged such that a first clearance is formed between an outer peripheral surface of the support shaft and an inner peripheral surface of the cylindrical bush, and a second clearance is formed between an outer peripheral surface of the cylindrical bush and an inner peripheral surface of the bearing hole.