An image capturing apparatus comprising: an image sensor in which at least part of pixels arranged in two dimensions are configured as focus detection pixels with divided-pupil; defect correction means (109, 110) configured to identify a pixel signal which requires defect correction among pixel signals output from the image sensor, and perform the defect correction on the identified pixel signal; extraction means configured to extract pixel signals of the focus detection pixels from pixel signals output from the image sensor, and phase difference detection means configured to detect phase difference information using pixel signals of the focus detection pixels with divided pupil, wherein the defect correction means uses correction information stored in a memory to identify the pixel signal which requires defect correction, wherein the extraction means uses the correction information to extract the pixel signals of the focus detection pixels, and wherein the correction information includes information for identifying positions of the focus detection pixels in the image sensor and information for identifying the position in the image sensor of the pixel which requires the defect correction, wherein the correction information further includes information for identifying the pupil division direction of the focus detection pixels, and wherein the phase difference detection means detects the phase difference information in accordance with the information for identifying pupil division direction and wherein the defect correction means performs defect correction on the pixel signal which requires the defect correction among pixel signals of the focus detection pixels extracted by the extraction means using pixel signals of the non-defective focus detection pixels whose direction of the pupil division is the same as that of the focus detection pixel which outputs the pixel signal which requires the defect correction. an image sensor in which at least part of pixels arranged in two dimensions are configured as focus detection pixels with divided-pupil; defect correction means (109, 110) configured to identify a pixel signal which requires defect correction among pixel signals output from the image sensor, and perform the defect correction on the identified pixel signal; extraction means configured to extract pixel signals of the focus detection pixels from pixel signals output from the image sensor, and phase difference detection means configured to detect phase difference information using pixel signals of the focus detection pixels with divided pupil, wherein the defect correction means uses correction information stored in a memory to identify the pixel signal which requires defect correction, wherein the extraction means uses the correction information to extract the pixel signals of the focus detection pixels, and wherein the correction information includes information for identifying positions of the focus detection pixels in the image sensor and information for identifying the position in the image sensor of the pixel which requires the defect correction, wherein the correction information further includes information for identifying the pupil division direction of the focus detection pixels, and wherein the phase difference detection means detects the phase difference information in accordance with the information for identifying pupil division direction and wherein the defect correction means performs defect correction on the pixel signal which requires the defect correction among pixel signals of the focus detection pixels extracted by the extraction means using pixel signals of the non-defective focus detection pixels whose direction of the pupil division is the same as that of the focus detection pixel which outputs the pixel signal which requires the defect correction.