This is Towa University. Sakura's father, Fujitaka, works here as an archeology professor. While it is not seen in many episodes, the university is often brought up in conversations between Fujitaka, Sakura, and Touya. It is also referenced on the bulletin board in the living room of their house. Fujitaka sometimes stays here overnight when he has a lot of work to finish.

10. Sakura and a Flowery Athletics Meet
22. Sakura and Her Kind Father
40. Sakura and the Sakura from the Dream (flashback)
69. Sakura Meets Clow Reed