A solid-state imaging device includes: a first chip including a pixel array in which a plurality of photoelectric conversion portions converting incident light into an electric signal are disposed; a second chip having an area in a plan view less than an area of the first chip in the plan view and electrically and physically connected to the first chip; and a support portion provided to cover an entire region which is not covered with the second chip in a surface of the first chip connected to the second chip and configured to support the first chip so that flatness of the first chip may be maintained.