An image pickup device includes: a pixel area where each of color image pixels arrayed in a matrix is divided into a plurality of focus detection pixels; a vertical scanning circuit and a device control circuit configured to read from the pixel area a first frame capable of constituting a color image and a second frame including phase difference information; a digital processing circuit configured to reduce color information of the second frame to reduce an amount of data; and an output circuit configured to output the first frame and the second frame via a transmission route with a number of lanes that is not the smaller of a first number-of-lanes and a second number-of-lanes required to output the first frame and the second frame, respectively.