An imaging device includes: an imaging section in which a plurality of unit pixels having a photoelectric conversion element are arranged in the form of a matrix; a reference signal generating section configured to generate a reference signal that increases or decreases with a passage of time; a comparison section that includes a differential amplifier including a first input terminal electrically connected to the reference signal generating section and a second input terminal electrically connected to the unit pixels and configured to compare voltages of the first input terminal and the second input terminal and is arranged for each column or for a plurality of columns of a pixel array of the imaging section; and a measurement section configured to measure a comparison time from when the comparison section starts comparison until the comparison ends and generate data corresponding to the comparison time.