An electro-optical inspection apparatus prevents adhesion of dust or particles to a sample surface, wherein a stage on which a sample is placed is disposed inside a vacuum chamber that can be evacuated, and a dust collecting electrode is disposed to surround a periphery of the sample. The dust collecting electrode is applied with a voltage having the same polarity as a voltage applied to the sample and an absolute value that is the same or larger than an absolute value of the voltage. Because dust or particles adhere to the dust collecting electrode, adhesion of the dust or particles to the sample surface can be reduced. Instead of using the dust collecting electrode, it is possible to form a recess on a wall of the vacuum chamber, or to dispose on the wall a metal plate having a mesh structure to which a predetermined voltage is applied.