A double-stranded nucleic acid molecule including (a) a sense strand which includes a nucleotide sequence corresponding to a target sequence indicated by any one of SEQ ID Nos.: 1 to 21, and (b) an antisense strand which includes a nucleotide sequence complementary to that of the sense strand specified in (a), wherein the double-stranded nucleic acid molecule is for suppressing the expression of at least one of APP and EBAG9 genes.