An exposure apparatus includes a light emitting device array in which a plurality of light emitting devices comprising light emitting sections formed onto a transparent substrate with a predetermined pattern and capable of being controlled and driven independently are arranged in a primary scanning direction to form a device row and a plurality of the device rows are arranged in a secondary scanning direction intersecting with the primary scanning direction. Further, the plurality of light emitting devices are aligned in the secondary direction with respect to a photosensitive material, and the plurality of device rows are sequentially illuminated on a time-division basis. In particular, the plurality of device rows are arranged with a pitch T expressed by T=(m-1/n)P when they are sequentially illuminated in a direction identical to the secondary scanning direction, and are arranged with a pitch T expressed by T=(m+1/n)P when they are sequentially illuminated in a direction opposite to the secondary scanning direction, where P is the pitch of an exposure pixel, m is an integer equal to or greater than 2, and n is the number of device rows arranged in the secondary scanning direction.