An imaging device, comprising: a pixel group in which unit pixels including a plurality of pixels receiving light fluxes having passed through different pupil areas of a photographing lens are provided in a form of a matrix; a plurality of types of color filters with different spectral transmittances provided in correspondence with the unit pixels; a microlens provided in correspondence with the color filter; a color information detection circuit which detects subject color information; and a pixel signal readout circuit which reads out a focus detection signal from the pixel group and reads out only a signal of the unit pixel in correspondence with a color filter associated with subject color information detected by the color information detection circuit.