According to an aspect of the invention, there is provided an exposure apparatus including an illumination optical system which forms an effective light source having a first polarization area where a mask pattern is illuminated with polarized light dominated by an electric vector component radial from a center position on an effective light source plane, and a second polarization area where the mask pattern is illuminated with light whose electric vector vibration is not biased in a specific direction; and a projection optical system which projects an image of the mask pattern onto an object to be processed.