
Quick answer — Hiroshi Isobe voices Yumetarou Haruna in Hamtaro, Kouji Azuma in Detective Conan: Sunflowers of Inferno.
Hiroshi Isobe voices Yumetarou Haruna (Hamtaro), Kouji Azuma (Detective Conan: Sunflowers of Inferno).
Yumetarou Haruna is voiced in Japanese by Hiroshi Isobe.