A semiconductor sample inspection device (1, 1A, 1B, 1C) for measuring electrical characteristics of a semiconductor sample to which a voltage is being applied by an external power supply device and which is being irradiated and scanned with light, and detecting a defective portion of the semiconductor sample based on the electrical characteristics, the device (1, 1A, 1B, 1C) comprising: a reference signal output section connected to the external power supply device in electrical parallel with the semiconductor sample and configured to output a reference signal according to an output of the external power supply device; a removal processing section configured to, based on the reference signal, perform processing for removing a noise component due to the output of the external power supply device on a test signal output from the semiconductor sample due to application of a voltage from the external power supply device, and to output the test signal on which the removal processing has been performed as a processing signal; characterized in comprising: a gain setting section configured to, based on a strength of the processing signal, set a gain of the reference signal output section, the gain with which the reference signal is output according to the output of the external power supply device; and an electrical characteristic measurement section configured to measure the electrical characteristics of the semiconductor sample based on the processing signal, the processing signal being subjected to the removal processing performed based on the reference signal from the reference signal output section for which the gain has been set by the gain setting section, wherein the reference signal output section is connected in electrical series to a reference member, the reference member being a semiconductor integrated circuit having the same electrical characteristics as the semiconductor sample, wherein no laser beam is emitted to the reference member, wherein the reference signal output section is configured to output the reference signal based on the current signal output from the reference member due to application of a voltage from the external power supply device. a reference signal output section connected to the external power supply device in electrical parallel with the semiconductor sample and configured to output a reference signal according to an output of the external power supply device; a removal processing section configured to, based on the reference signal, perform processing for removing a noise component due to the output of the external power supply device on a test signal output from the semiconductor sample due to application of a voltage from the external power supply device, and to output the test signal on which the removal processing has been performed as a processing signal; characterized in comprising: a gain setting section configured to, based on a strength of the processing signal, set a gain of the reference signal output section, the gain with which the reference signal is output according to the output of the external power supply device; and an electrical characteristic measurement section configured to measure the electrical characteristics of the semiconductor sample based on the processing signal, the processing signal being subjected to the removal processing performed based on the reference signal from the reference signal output section for which the gain has been set by the gain setting section, wherein the reference signal output section is connected in electrical series to a reference member, the reference member being a semiconductor integrated circuit having the same electrical characteristics as the semiconductor sample, wherein no laser beam is emitted to the reference member, wherein the reference signal output section is configured to output the reference signal based on the current signal output from the reference member due to application of a voltage from the external power supply device.