An imaging device is provided which allows an increase in the degree of freedom of its layout. The imaging device includes a first semiconductor substrate including a sensor pixel for performing photoelectric conversion, and a second semiconductor substrate including a readout circuit for outputting a pixel signal according to an electric charge output from the sensor pixel. The second semiconductor substrate is laminated on the one surface side of the first semiconductor substrate so as to configure a laminated body. The second semiconductor substrate includes a first surface facing the first semiconductor substrate, and a second surface located opposite to the first surface. The first transistor included in the readout circuit is disposed in the first surface, and the second transistor included in the readout circuit is disposed in the second surface.