1. An examination device comprising: a light irradiation unit that irradiates at least a part of an object to be examined with light having a specific wavelength as a principal component, while an irradiation area is being modified; an imaging unit that images an irradiated position, on the object to be examined, of the light having the specific wavelength as a principal component, and that captures an image of the object to be examined; a spectroscope that disperses scattered light of the light irradiated by the light irradiation unit onto the object to be examined; a detector that detects an intensity of the scattered light dispersed by the spectroscope; an attached state estimation unit that detects an attached state of an attached matter on the object to be examined from the intensity of the light detected by the detector; an irradiation area detection unit that, from the irradiated position; captured by the imaging unit; of the light having the specific wavelength as a principal component and the captured image, generates irradiation area information by associating the irradiated position of the light having the specific wavelength as a principal component and a pixel of the imaging unit; an image processing unit that, based on the attached state of the attached matter and the irradiation area information, generates an image of the attached matter present in an area imaged by the pixel of the imaging unit; and a synthesizing unit that generates a synthesized image by synthesizing the captured image and the image of the attached matter.