An exposure head includes a plurality of light emitting element array chips. A first distance from a first side which is one of two long sides of each of the plurality of light emitting element array chips to one long side of a sealing area which is parallel to and proximate to the first side is shorter than a second distance from a second side which is another one of the two long sides to another long side of the sealing area which is parallel to and proximate to the second side, and a third distance from the first side to one long side of a light emitting area which is parallel to and proximate to the first side is shorter than a fourth distance from the second side to another long side of the light emitting area which is parallel to and proximate to the second side.