PCT No. PCT/EP98/02965 Sec. 371 Date Jan. 14, 1999 Sec. 102(e) Date Jan. 14, 1999 PCT Filed May 20, 1998 PCT Pub. No. WO98/52879 PCT Pub. Date Nov. 26, 1998An object of the present invention is to provide a synthetic silica glass optical material which exhibits excellent transmittance as well as durability for high output power vacuum ultraviolet rays, being emitted from, for example, ArF excimer lasers and Xe2 excimer lamps, and to provide a method for producing the same. A synthetic silica glass optical material for high output power vacuum ultraviolet rays made from ultra high purity synthetic silica glass for use in the wavelength region of from 165 to 195 nm, containing OH groups at a concentration of from 5 to 300 wtppm with a fluctuation width in OH group concentration ( DELTA OH/cm) of 10 wtppm or less, containing hydrogen molecules at a concentration of from 1x1017 to 1x1019 molecule/cm3 with a fluctuation width in hydrogen molecule concentration ( DELTA H2/cm) of 1x1017 molecule/cm3 or lower, and containing chlorine at a concentration of 50 wtppm or lower. Also claimed is a method for producing the same.