Halomonas (Deleya) sp. alpha-15 produces new co-factor binding soluble glucose 3-dehydrogenase (G3DH), which oxidizes the third hydroxy group of pyranose. This study investigated the condition of efficient production of G3DH using Halomonas (Deleya) sp, alpha-15. This enzyme was inducible, and alpha-methyl-D-gluco side, isopropyl-thiogalactopyranoside (IPTG) and lactose were revealed to be suitable carbon sources for G3DH induction. Maximum G3DH production was achieved by using minimal medium containing 0.8% (w/v) lactose with a productivity of 470U/l.