Isamu Tanonaka

was a Japanese voice actor from Taitō, Tokyo. He was best known for voicing Medama Oyaji in nearly every adaptation of Shigeru Mizuki's GeGeGe no Kitarō made during his lifetime.

During his life he had been attached to Gekidan Tōgei and then Theatre Echo; he was attached to Aoni Production at the time of his death. He had a naturally deep voice but became famous for voicing characters with a high pitched voice. In addition to GeGeGe no Kitarō, he also had prominent roles in Tensai Bakabon (as the first voice of Honkan-san), Mazinger Z (as Mucha), Paul's Miraculous Adventure (as Doppe), Magical Princess Minky Momo (as Sindbook), Akuma-kun (as Youaltepuztli), Dr. Slump & Arale-chan (as Gara and Akira Toriyama), Dragon Quest: Dai no Daibōken (as Brass), and the Shin Megami Tensei: Persona series (as Igor).