PURPOSE: To allow high accurate collation by a manual test system and ensure of information on fluctuation width of measurement by discriminating and displaying reading-out check results in accordance with degree of satisfaction with a reading-out cycle.

CONSTITUTION: In accordance with an address of a program from an address register through a skew correction circuit a high speed IC is read out, checked by program data and a comparator, and "fail" and "pass" data are outputted and supplied to a fail and a pass FF51 and FF52, respectively. Checked results by these FF51 and FF52 are logically executed, and the following three types of display are carried out; not satisfied with all reading-out cycles, satisfied with only some reading-out cycles and satisfied with all reading-out cycles. In accordance with these displays manual collation of a skew correction circuit by "SHMOOPLOT" can be carried out at a high accurate level, information on measuring fluctuation width of a test system itself can be secured and a test of a high speed IC can be carried out properly.