There are four large buildings on the south side of JR Osaka Station, each joined underground.
The 1st and 2nd floors underground include a food court with reasonably-priced high-quality restaurants, making the area popular with office workers both for lunchtime and dinner.
Many of the businesses have been there for a long time, giving it a bit of a retro atmosphere.
The 2nd building specializes in ramen and the 3rd building in udon.
Be aware that many of the restaurants close on public holidays.