The disclosure provides an inspection device including a light source module, an image receiving module and a processing unit. The light source module emits a first incident light and a second incident light to a device under test (DUT). The image receiving module receives a first image corresponding to the DUT irradiated by the first incident light, and receives a second image corresponding to the DUT irradiated by the second incident light. The processing unit calculates the contrast ratio of the first image and the second image to obtain a high-contrast image for inspection.