PURPOSE: A light scanning unit is provided to prevent ghost and control bow phenomenon of deterioration of beam diameter or scanning line. CONSTITUTION: A light source emits an optical beam. An optical deflector(150) deflects the light beam. An imaging optical system images the light beam deflected at the light deflection unit on scanned surface. The imaging optical system has at least two optical elements(160,170). At least two imaging optical elements is arranged at optical path between the optical deflection unit and scanned surface.
