Pin-grid array type socket

An eccentric member 5, having a first shaft portion and the eccentric portion 52 a, the first shaft is provided with a recess portion 51a, the central axis of the eccentric portion is different from the axis of the first shaft portion 51 and the eccentric portion 51 end of the first shaft portion 51 is continuously formed. 51a has a concave recess, which boundary line is divided into a rectangular shape on the first surface of the shaft portion 51 of the recess 51a. A flat-blade screwdriver and mating recess 51a and a flat-blade screwdriver is rotated, so that the cover 3 slide in the housing 2 above the base housing.