an embodiment of the present invention provides a circuit board and a socket having mechanical connector for easily connecting and disconnecting a semiconductor integrated circuit device to and from the circuit board . another embodiment further includes a sub - circuit board for electrically connecting the socket to the circuit board . the socket includes a socket body and a number of socket leads . the socket leads are shaped to compress elastically when inserted in a hole and thereby make contact between the socket leads and inner walls of the holes of the circuit board . the sub - circuit board has connection leads , which make contacts with the through holes of the circuit board in the same manner as the socket leads of the present invention .