To provide new microorganisms enabling only neoagarobiose to be produced by selectively lowering the activity of an enzyme that splits neoagarobiose into a monosaccharide while keeping the activity of an enzyme that splits agar-agar into neoagarobiose in producing neoararobiose by splitting agar-agar, and to provide a method for producing the neoagarobiose utilizing the microorganisms.

The new microorganisms(FERM AP-20514) belonging to the genus Cellvibrio are provided, being agar-agar splitting bacteria with agar-agar as the sole carbon source. The method for producing neoagarobiose with agar-agar as substrate utilizing the microorganisms is also provided, being characterized by involving conducting an ammonium sulfate or ammonium chloride treatment.