PURPOSE: To select a test case having high importance and to efficiently test a program by providing the titled device with a test case selection supporting device for supporting the selection respective test cases in all test cases in the order of importance.

CONSTITUTION: The test case selection supporting device 1 supports the selection of respective test cases in all the test cases in the order of importance in the whole functions of a program inputted from a user based on the information relating to the program. A test data generator 2 generates test data for the selected test case. An objective program executing device 3 inputs the test data and tests the objective program. The result of the test is evaluated by a result evaluating device 4 and the evaluated result is outputted from an evaluated result output device 5. While observing the evaluated result outputted from the device 5, the user can detect a bug having the highest importance for the whole functions of the program.