The purpose of the present invention is to provide a fundamental treatment method for mitochondrial genetic diseases caused by a mutation of mitochondrial DNA, and a pharmaceutical composition therefor. This problem can be solved by a polyamide compound which binds to a target double-stranded mitochondrial DNA which has a sense strand DNA consisting of the base sequence represented by 5'-ATGGCAGAGCCCGGTAATCGCATAA-3' and an antisense strand DNA consisting of the base sequence represented by 5'-TTATGCGATTACCGGGCTCTGCCAT-3'. This double-stranded mitochondrial DNA includes an A/T pair of A in position 1 of the sense strand and the complementary T, an A/T pair of A in position 8 of the sense strand DNA and the complementary T, a G/C pair of G in position 9 of the sense strand DNA and the complementary C, a G/C pair of G in position 14 of the sense strand DNA and the complementary C, or a T/A pair of T in position 15 of the sense strand DNA and the complementary A.
