The object of the present invention is to provide a method of producing
antisense oligonucleotide, in which the possibility of forming a
substantially complementary double-stranded chain between each region of
a nucleotide sequence in mRNA and a region other than said region is
expressed as a numerical value, and oligonucleotide substantially
complementary to a region with a smaller numerical value is prepared as
antisense oligonucleotide. The resulting antisense oligonucleotide can be
used effectively in the antisense oligonucleotide method.