PURPOSE: To eliminate such faults as detachment of a packing due to tension of a lead wire, loosening, hanging down, etc. of the lead wire, and also to make a complicated packing installing process unnecessary at the time of assembling, by installing a lead wire drawing-out part of an electric apparatus used for a optical scannner, to the outside of an enclosed cover of the light scanner.

CONSTITUTION: Various members extending from a laser light source unit 1 to a cylindrical lens 12 on an optical path, for changing laser light emitted from a laser light source unit 1 for constituting a scanning means, to a scanned light and leading it to a photosensitive body are incorporated in a cover 14. This cover 14 is formed like a box whose upper part is opened, and a seat surface 14a of the upper end is covered with a cover 15 and clamped with a screw 16, and closed up tightly,leaving a scanning light emitting window. Each electric apparatus is installed by positioning its lead wire drawing-out part at the outside of the cover 14. First of all, as for the laser light source unit 1, a flange 1a is made to adhere tightly to the seat surface of the outside of the cover 14, and in a state that is screwed to the seat surface from the outside of a radiation fin 1b, a cylinder part 1c to which a collimating lens for converting a diverging light from a semiconductor laser to parallel rays is engaged to a hole 14c1, and regulated so that the laser light can be emitted in the prescribed direction in the cover 14.