Certain embodiments provide a solid-state imaging device including: a semiconductor substrate of a first conductivity type having a first face and a second face that is the opposite side from the first face; a plurality of pixels provided on the first face of the semiconductor substrate, each of the pixels including a semiconductor region of a second conductivity type that converts incident light into signal charges, and stores the signal charges; a readout circuit provided on the second face of the semiconductor substrate to read the signal charges stored in the pixels; an ultrafine metal structure placed at intervals on a face on a side of the semiconductor region, the light being incident on the face; and an insulating layer provided between the ultrafine metal structure and the semiconductor region.