To obtain a method and a device for testing a device to be tested by which a device to be tested in which hazard is caused can be detected as a defective product.

This method is for testing a device to be tested by which the test of a device 1 is performed by comparing output data from the device 1 with an expected value of the output data on the basis of the timing of a strobe signal. When rise/fall edges are detected twice or more between the strobes of different expected values (from the previous comparison time to the present comparison time) or a rise/fall edge is detected even only once between the strobes of the same expected values, it is discriminated that hazard is caused in the device 1 to be tested.