Mitsunori Okamoto (岡本 充功) is a Japanese politician of the Constitutional Democratic Party, who is a member of the House of Representatives in the Diet (national legislature). A native of Yōkaichi, Shiga and graduate of Nagoya University, he obtained his medical license in 1996 and received his Ph.D in medicine from Nagoya University. He was elected to the House of Representatives for the first time in 2003. He was defeated in the 2005 election. He ran again to the House of Representatives in 2009 in the 9th district of Aichi defeating Prime Minister from 1989 to 1991, Toshiki Kaifu in a stunning upset. After losing his seat and being in 6th of 5 elected candidates for the CDP in the Tōkai proportional representation block during the 2021 election, he won a constituency in 2024, defeating Yasumasa Nagasaka in Aichi 9th district.