An imaging device includes a light source layer having imaging light source units for radiating the imaging light containing a first wavelength on an object to be imaged, a detection layer having detection elements for detecting the light of the first wavelength radiated from the light source units, and a light-blocking unit interposed between the light source layer and the detection layer. The light source layer is held between the detection layer and the object to be imaged. The light-blocking unit is arranged in such a manner as to block the direct radiation of at least part of the light radiated from the light source units to the detection elements.