PURPOSE: To generate data items for test quickly without contradictions by selecting items subordinated to a main item on a basis of the subordinative relation, which is indicated from a display, to generate subordinative data.

CONSTITUTION: Subordinative relations between items are indicated on a display 11, and data is generated on a basis of these indications. For example, the item of address 1 is main item (M), and the item of address 2 is subordinate item to indicate reading (R), and the item of postal code number is a subordinate item also to indicate a postal code number (Y) of the main item. Automatic data generating part 12 transfers the control to a related data generating part 14 which generates data of subordinate items. The related data generating part 15 obtains data of the main item from a main item data table 16 at random and obtains values of subordinate items subordinated to the main item from a subordinate item data table 17 to generate output data.