An imaging device having a shooting optical system, including an imaging element having a pixel array capable of generating image signals regarding light from a subject coming through the shooting optical system, and a focus-detection pixel line having pairs of pixels, the pixels of each of the pairs receiving luminous fluxes from the subject coming through a pair of individually corresponding partial regions of an exit pupil of the shooting optical system; a rapid-fire shooting unit configured to perform rapid-fire shooting to generate image signals at the pixel array on each exposure and to generate certain signals at the focus-detection pixel line; a focus detection unit configured to perform focus detection by a phase-difference detection method on the basis of the certain signals; and a focus adjustment unit configured to perform focus adjustment during each interval of the exposures on the basis of a result of focus detection.