Proposed is an inspection device that is provided with: an illuminating optical unit that irradiates a discretionary region of a sample with light; a control unit that gives instructions to the illuminating optical unit; and at least one detection unit that detects light transmitted from the sample. The illuminating optical unit includes a light source unit that generates light, and an electrooptic element unit to which the light generated by the light source unit is inputted, and on the basis of the instructions given from the control unit, the electrooptic element unit adjusts the light to be in a desired polarization state, said light having been generated by the light source unit, and irradiates the sample with the light.