PURPOSE: To measure various flat package type ICs by dividing a conventional socket jig into common substrates together with a socket for combination, and further dividing the sockets for combination and allowing them to be replaced.

CONSTITUTION: Four divided sockets 5 for combination has a contactor 2 which contacts the contactor (a) of an IC 4, a contactor 2a for an IC measuring circuit, and wiring internally. The sockets 5 are fitted in the common substrates 7 so that respective socket side contactors 2a and common-substrate side contactors 8 are connected mutually. Then the measuring flat package type IC 4 is pressed and fitted from above by a lid so as to perform an electric connection between its lead 4a and contactor 2a. The other terminal of the contactor 8 of a substrate 7 is connected to the IC measuring circuit to measure the IC 4. Consequently, various flag package type ICs are measured.