To perform uniform exposure by making uniform interference fringes of laser light formed through a fly-eye lens and reducing illuminance unevenness of the laser light.

A laser exposure device includes: a laser light source 1; a first fly-eye lens 2 which makes the uniform intensity distribution of light in a surface to be orthogonally crossed with an optical axis 9, and enlarges the cross section shape of the laser light by radially releasing emission light after concentrating the light once; a first condenser lens 4 for making laser light with the cross section shape enlarged therein into parallel light; a second fly-eye lens 5 for making an uniform light intensity distribution in an illumination region of a photomask 12 which is irradiated with the laser light; a diffuser panel 3 arranged between the first fly-eye lens 2 and the first condenser lens 4, so as to diffuse the laser light; and a transparent rotary plate 6 arranged on the laser light emission side of the second fly-eye lens 5, having a face 6a inclined with respect to the optical axis 9, and rotating with the optical axis 9 as a center.