Hiroshi Uchiyamada is a background character who is regularly seen on Kodomo no Omocha. He is overweight, and many jokes revolve around him being such. He is the only one of the other children besides Sana on the show to have many lines.
He is shown to work often with Zenjiro, and acts as his stand-in at times. He is also shown to have some level of popularity, as he is noticed on his own when he works outside of his normal work.