PURPOSE: To facilitate the preparation of a test program and to shorten a time necessary to a debugging by preparing wholly the program of a function common to respective tests and designing the test contents by the combinations.

CONSTITUTION: At test programs 22-1,22-2,22-3...2-l, the same EXECUTER part 36 is provided, either of the programs is successively selected by the operator data of an operation code data part 38 and successively, executed by using the data of a test data part 26. Consequently, the selection sequence of respective programs at an EXECUTER part 36 is determined, the programming of the operation code data part 28 is executed, the data necessary to them are described to a test data part 26 and thus, test programs 22-1,22-2,22-3,...22-l can be prepared. For such reason, even when the test processing and the test item are increased, a program preparation labor can be decreased.