Abstract: The present technology relates to a semiconductor device and an imaging device capable of efficiently dissipating heat generated in a semiconductor package including a resin. A first substrate, a second substrate, a wiring layer that is located between the first substrate and the second substrate, and a slit that penetrates the first substrate and reaches the wiring layer are provided. The gap is provided for each wiring provided in the wiring layer. The present technology can be applied to, for example, a semiconductor device in which a chip on which an imaging element is formed and a chip that processes a signal from the imaging element are stacked.