Dark current from a transfer transistor is suppressed and power-supply voltage in a second semiconductor substrate is lowered. A solid-state image pickup device includes a pixel array, a plurality of common output lines receiving signals read out from a plurality of pixels, a transfer scanning unit sequentially driving the plurality of transfer transistors, a signal processing unit processing the signals output to the common signal lines, and a level shift unit making amplitude of a pulse supplied to a gate of the transfer transistor larger than amplitude of a pulse supplied to a gate of a transistor constituting the signal processing unit. The pixel array and the level shift unit are arranged on a first semiconductor substrate, whereas the plurality of common output lines and the signal processing unit are arranged on a second semiconductor substrate.