An object of the present invention is to provide an oligonucleotide useful as a therapeutic agent for dyslipidemia that has excellent binding affinity to the PCSK9 gene as well as stability and safety. The oligonucleotide of the present invention contains a sugar-modified nucleoside, the sugar-modified nucleoside has a bridging structure between 4-position and 2-position, and the oligonucleotide can bind to the human PCSK9 gene. Also, the present invention provides a therapeutic agent for dyslipidemia containing the oligonucleotide as an active ingredient, and the therapeutic agent preferably contains a bioabsorbable material as a carrier. The bioabsorbable material is preferably atelocollagen or peptide gel.
