The present invention aims to provide an antisense oligonucleic acid with reduced hepatotoxicity. The antisense oligonucleic acid according to the present invention is characterized in that it has a base length of not less than 7nt and not more than 30nt, wherein nucleic acid residues of not less than 1nt and not more than 5nt respectively from the both terminals are 2',4'-bridged nucleic acids, 2',4'-non-bridged nucleic acid residue(s) is(are) present between the above-mentioned both terminals, and one or more bases in the nucleic acid residue(s) of the above-mentioned 2',4'-non-bridged nucleic acid residue(s) is/are modified.
