Provided is an imaging apparatus including an image sensor. In the image sensor that includes a valid pixel area in which a plurality of valid pixels each having a photoelectric conversion unit is disposed, a first reference pixel area in which a plurality of first reference pixels each having a light-shielded photoelectric conversion unit is disposed, and a second reference pixel area in which a plurality of second reference pixels each having no photoelectric conversion unit is disposed, when outputs of the plurality of valid pixels are added to be read, outputs of the plurality of first reference pixels are added by the addition unit to be read, and outputs of the plurality of second reference pixels are read without being added by the addition unit. Thus, noises can be effectively corrected even in the small number of invalid pixels areas.