Cancer research and neuroscience laboratories will be housed in the new building, which forms part of a wider Maindy Park campus plan on a disused 9-acre railway site in Cardiff.
The whole project is expected to take more than a decade to complete.
Its design was rated “excellent” in an independent environmental assessment and will use sustainable building materials and energy efficiency systems.
Professor Tim Wess, Cardiff University’s pro vice-chancellor for estates, said: “This new building will help regenerate an important part of our city centre, establishing world-class research teams to address issues which affect us all.
“We have worked very closely with the community and Cardiff council on developing our plans and we are very grateful for all their interest and support.”