The invention provides an artificial sgRNA and a CRISPR/Cas9 system by combining the artificial sgRNA and Cas9. Activity of the sgRNA can be retained even when a nucleotide linker region for forming a single strand by linking the 3′-terminal of crRNA and the 5′-terminal of tracrRNA in sgRNA is substituted with an amino acid derivative linker, when the linker region existing between stem-loop 1 and stem-loop 2 of tracrRNA and/or the loop portion of stem-loop 2 are/is substituted with an amino acid derivative linker, or when an amino acid derivative linker is added/inserted into the vicinity of the 5′-terminal and/or the 3′-terminal of sgRNA. Stability in vivo can be improved by introducing one or more amino acid derivative linkers into the sgRNA.