An image processing apparatus and an image processing method capable of discriminating with good precision a cause of image degradation that occurs in a value of a pixel adjacent to a focusing pixel, and of appropriately performing correction. When correcting a value of an imaging pixel adjacent to a focusing pixel, it is determined whether the value of the correction target pixel is influenced by flare based on a value of an imaging pixel adjacent to the focusing pixel that exists in a vicinity of a correction target pixel, and values of a plurality of imaging pixels that exist in a vicinity and are not adjacent to the focusing pixel. An appropriate method for correcting the influence of flare is used if it is determined that the value of the correction target pixel is influenced by flare.