[Problem] To provide an improved ²-fructofuranosidase which enables the production of kestose with high efficiency while reducing the amount of a by-product such as nystose produced during the production of kestose. [Solution] An improved ²-fructofuranosidase comprising an amino acid sequence which is produced by introducing an amino acid mutation into an amino acid sequence for a ²-fructofuranosidase having 60% or higher identity to the amino acid sequence for wild-type ²-fructofuranosidase which is represented by SEQ ID NO: 2, wherein the amino acid mutation is such a mutation that, when amino acid sequence alignment is performed, a histidine (H) residue corresponding to the position as numbered from the N-terminal of the amino acid sequence for the wild-type ²-fructofuranosidase which is represented by SEQ ID NO: 2 can be replaced by an arginine (R) residue or a lysine (K) residue.
