The corporation’s current HQ in Llandaff will shut and staff will relocate to the new building in Capital Square in 2018.
The new 150,000 sq ft building will be part of the wider Capital Square development around Cardiff Central train station which includes relocating the bus station.
Construction work is scheduled to start as early as next summer on the Foster + Partners designed scheme.
Cardiff council leader Phil Bale, said the new building would fast-track its plans for the bus station area.
He said: “This type of investment comes around once in a generation. It boosts Cardiff’s emergence as a leading centre for creative industries in Europe.”