An imaging device includes an imaging unit that generates image data on the basis of a first power voltage, an image processing unit that performs image processing on the image data on the basis of a second power voltage, a reference voltage generating unit that generates a first reference voltage on the basis of the first power voltage and a first flag generating unit that generates a first flag signal for the second power voltage on the basis of a comparison of the second power voltage and the first reference voltage and configured to output the first flag signal.