To prevent deterioration of resolution caused by variation of characteristics of a lens array in a light emitting element head utilized in an optical writing device such as a printer, a copying machine, a facsimile and the like using an electrophotographic recording system, when a plurality of lens arrays are employed.

When the lens array 8 is to be placed above an LED substrate 5 on which an LED chip 6 is placed, the lens array 8 is placed on a SLA placing surface 3j of an SLA support clamp 3, thus setting the height from the LED substrate 5. In the case a plurality of lens arrays 8 are utilized, the SLA support clamp 3 having the height of the SLA placing surface 3j corresponding to the respective characteristics of each lens array 8 is provided, so that the deterioration of resolution is prevented.