Abstract: [Problem to be Solved ] Provided is a nucleic acid complex, preferably a double-stranded nucleic acid complex, having an excellent effect of suppressing the expression of a target gene. [Solution] The problem is solved by using a nucleic acid complex, preferably a double-stranded nucleic acid complex, comprising an active moiety comprising an antisense nucleic acid complementary to a transcript, for example, a transcript of a target gene, and a carrier moiety comprising a nucleic acid complementary to the nucleic acid, and having at least one bulge structure.

Abstract: Provided is a nucleic acid complex, preferably a double-stranded nucleic acid complex, having an excellent effect of suppressing the expression of a target gene. Further provided is a nucleic acid complex, that is, a double-stranded nucleic acid complex, comprising an active moiety comprising an antisense nucleic acid complementary to a transcript, for example, a transcript of a target gene, and a carrier moiety comprising a nucleic acid comprising DNA, preferably a DNA-based nucleic acid, which is complementary to the above-described nucleic acid.