To provide an optical writing head which is capable of high-speed printing without dot misregistration, vertical streaks and ghost images, is superior in the dimensional stability of a distance between optical axes, has a good aged profile of a joint part environment, can shorten a jointing assembling tact and can cope with tilting dimensional variations in orientations XYZ.

The optical writing head (100) is assembled by direct jointing by positioning a first member (10) where an LED light emitting part (12) is mounted and a second member (20) where a lens mirror part (21) is mounted while a constant distance of optical axes is maintained.