An imaging element which outputs an image signal acquired by an imaging unit having a plurality of pixel portions is provided. The imaging element receives a target luminance value from an imaging device and executes exposure control in the imaging element on the basis of an accumulation time of the pixel portion and a gain for an output signal of the imaging unit, which correspond to the target luminance value. The imaging element instructs the imaging device to perform exposure control if a luminance value of a subject exceeds an exposure control range in the imaging element.