An imaging device comprising: an image sensor includes a first focus detection pixel being arranged at a position corresponding to a first color filter of the imaging pixel, and a second focus detection pixel being arranged at a position corresponding to a second color filter, a read-out section mixes a plurality of pixel signals including the output of the first focus detection pixel and reads out a first mixed pixel output, in mixing and reading out the outputs of the imaging pixels corresponding to the first color filter, while the read-out section mixes a plurality of pixel signals without including the output of the second focus detection pixel and reads out a second mixed pixel output, in mixing and reading out the outputs of the imaging pixels corresponding to the second color filter.