An imaging device includes an image sensor and an estimating circuit. The image sensor includes a plurality of pixel units disposed in a two-dimensional array, each equipped with a plurality of imaging pixels with varying spectral sensitivity characteristics set regularly, and focus detection pixels with sensitivity over a range encompassing the spectral sensitivity of the pixel units. The estimating circuit determines an image output structure corresponding to the position of each focus detection pixel based upon outputs from the imaging pixels present around the focus detection pixel and estimates the image output at the focus detection pixel based upon the image output structure and the output from the focus detection pixel.