An imaging device that has a structure where a transistor is used in common by a plurality of pixels and is capable of imaging with a global shutter system is provided. A transistor that resets the potential of a charge detection portion, a transistor that outputs a signal corresponding to the potential of the charge detection portion, and a transistor that selects a pixel are used in common by the plurality of pixels. A transistor is provided between a power supply line and a photoelectric conversion element. Exposure is performed by turning on the transistor. Imaging data is retained in a charge retention portion by turning off the transistor.