A DOE homogenizer including a plurality of parallel lasers emitting Gaussian beams of a diameter d along beam lines extending in a z-direction and aligning at a pitch p in an x-direction, and off-axis DOEs diffracting the Gaussian laser beams at inclining diffraction angles, making quasi-uniform density qw (qw) stripe-sectioned beams on an image plane I (xy-plane) which is distanced by a focal length f from the DOEs and aligning at the pitch p on an x-direction extending base line K vertical to the beam lines in an order of larger inclining diffraction angles outward and smaller inclining diffraction angles inward on extensions of the beam lines of the lasers, the DOEs diffracting the laser Gaussian beams into the quasi-uniform density stripe-sectioned beams, superposing the diffracted beams partially at edges and making a unified x-direction extending quasi-uniform beam on the image plane I.