An imaging device for an endoscope includes an image pickup lens, a spectral characteristics variable optical element, and a CCD. The spectral characteristics variable optical element passes only light of a specific wavelength in accordance with the distance between first and second plates, and reflects light of the other wavelengths. The CCD converts the light reflected from the variable optical element into an image signal. In fluorescence endoscopy, a fluorescent labeling agent is administered on an internal body part to be examined. Application of excitation light to the body part causes the fluorescent labeling agent to emit fluorescence. The variable optical element removes the excitation light from the fluorescence by regulation of the distance between the first and second plates.
