A solid-state imaging device includes a first substrate, a second substrate, a plurality of first connectors, and a plurality of second connectors. The plurality of first connectors are configured to transmit a first signal. The plurality of second connectors are configured to transmit a second signal. The first signal has at least two levels, and the levels of the first signal discretely vary between the at least two levels. The second signal is a continuous time signal. A first area of a first region is smaller than a second area of a second region. The first region is a projection region of each of the plurality of first connectors in a principal surface of the first substrate. The second region is a projection region of each of the plurality of second connectors in the principal surface.