In the manga.
In the anime.
The House of Ujuin is the most luxurious residence in Kasukabe. It appears rarely in the series.
It is very large, surrounded by a high wall, has a large garden and a huge entrance. It is home to Ms. Ujuin, the owner of the house, with her son Mashumaro and his dog, and Tane Higashimatsuyama works as a guard.