PROBLEM TO BE SOLVED: To provide a method by which the interface state density of a semiconductor interface having a structure other than an MIS structure can be obtained and by which the interface state of a semiconductor interface and the interface state of an exposed semiconductor surface can be evaluated.SOLUTION: The interface state of a first semiconductor layer 16 of a semiconductor device is evaluated, the semiconductor device having a first semiconductor layer 16 and a second semiconductor layer 20 hetero-jointed to the first semiconductor layer 16, and also having a conductive channel layer 17 formed along a hetero-joined interface 18. To evaluate an interface state, while constant electric current is caused to flow in the conductive channel layer 17 by a constant current power source, a pillar is pressed toward the semiconductor device 10, thereby applying external pressure such that the semiconductor 10 is warped. The application of the external force causes tensile stress, as shown by the arrows
