1. An image processing apparatus comprising: an image acquiring unit that acquires an image of a subject imaged by an image capturing lens; a face detecting unit that detects face information corresponding to a person's face from the image acquired by the image acquiring unit; an image angle-of-view calculating unit that calculates an angle of view of a portion including the face in the image based on the face information detected by the face detecting unit; a correction necessity determining unit that determines whether distortion correction of the image needs to be performed, based on whether the portion including the face within the angle of view calculated by the image angle-of-view calculating unit includes a distorted part that is determined according to distortion characteristics of the image capturing lens; and an image correcting unit that performs distortion correction on the image when the correction necessity determining unit determines that the distortion correction of the image needs to be performed.