Disclosed are a polarizer comprising a circularly polarized light separation layer in which two or more cholesteric liquid crystal polymer layers are laminated with each other in a close contact state in a long-short order based on a center wavelength of reflected light, said circularly polarized light separation layer changing in helical pitch in the direction of thickness, a retardation layer arranged on the long-wavelength side of said center wavelength, and a polarizing plate containing a dichroic substance and disposed on the retardation layer, as so desired; a lighting device in which a surface light source is arranged on the circularly polarized light separation layer side of said polarizer; and a liquid crystal display in which said polarizer or said lighting device is arranged on the visual back face side of a liquid crystal cell, directing the retardation layer side thereof to the liquid crystal cell.