The present invention provides the following: a vector for inserting a desired nucleic acid into a predetermined site of a nucleic acid comprising a region formed of a first nucleotide sequence, the predetermined site, and a region composed of a second nucleotide sequence, in the stated order in the 5-to-3 direction, wherein the vector comprises a region formed of the first nucleotide sequence, the desired nucleic acid, and the second nucleotide sequence in the stated order in the 5-to-3 direction a kit that includes this vector a method of inserting a nucleic acid comprising a step for introducing this vector into a cell a cell acquired by this method and an organism comprising this cell.
