An object of the present invention is to obtain a clear absorbed current image without involving the difference in gain of amplifier between inputs, from absorbed currents detected by using a plurality of probes and to improve measurement efficiency.In the present invention, a plurality of probes are brought in contact with a specimen. While irradiating the specimen with an electron beam, currents flowing in the probes are measured. Signals from at least two probes are input to a differential amplifier. An output of the differential amplifier is amplified. On the basis of the amplified output and scanning information of the electron beam, an absorbed current image is generated. According to the invention, a clear absorbed current image can be obtained without involving the difference in gain of amplifier between inputs. Thus, measurement efficiency in a failure analysis of a semiconductor device can be improved.