To cut down the production cost and the running cost by reducing the number of UV sources required for curing of waste ink, in an apparatus for treating the waste UV inks that are curable by being irradiated with UV light, and also to make a waste liquid tank reusable by removing waste liquid therefrom.

The apparatus for treating the waste UV inks includes: the waste liquid tank for storing the waste UV inks curable by being irradiated with UV light; and an UV light emitting section for irradiating the waste ink in the waste liquid tank with UV light, using LED. The waste liquid tank has a rotating shaft in the vertical direction and can rotate about the shaft, and has a cylindrical outer periphery. The apparatus for treating the waste UV inks is provided with: a rotating portion for rotating the waste liquid tank; and a control section for controlling the operation of the UV light emitting section and the rotating portion.