[Problem] To expand the dynamic range, increase the frame rate, and reduce power consumption during photoelectric conversion.
[Solution] An imaging device includes a pixel unit that outputs a photoelectrically converted pixel signal to a signal line, an AD converter that performs AD conversion on the pixel signal on the signal line and determines illuminance based on the pixel signal, and a switching circuit that switches whether to input the pixel signal on the signal line to the AD converter and whether to output the illuminance determination signal determined by the AD converter to the signal line in conjunction with each other. The pixel unit includes a first photoelectric conversion portion, a conversion efficiency adjustment circuit that switches the conversion efficiency when converting the charge photoelectrically converted by the first photoelectric conversion portion into voltage, a first readout circuit that outputs a pixel signal corresponding to the charge photoelectrically converted by the first photoelectric conversion portion to the signal line, and a holding circuit that holds the determination signal.