A process for producing a noble-metal-supporting ceramic is provided which includes fixing a platinum nanocolloid to a base. The ceramic enables the nanocolloid to continuously function as a catalyst over long. The process comprises: a deposition step in which a base constituted of a ceramic is brought into contact with a dispersion containing a noble-metal nanocolloid and colloidal silica, the noble-metal nanocolloid comprising fine noble-metal particles constituted of platinum and having a volume-average particle diameter of 1-10 nm and a colloid-forming agent which is an organic substance rendering the fine noble-metal particles colloidal, thereby obtaining a deposition product； and an oxidative removal step in which the deposition product is heated in an oxidizing atmosphere to oxidatively remove the colloid-forming agent. Since the fine noble-metal particles in a dispersed state are deposited as a colloid having extremely high dispersibility on the base, the extremely fine noble-metal particles can be evenly distributed on the surface of the base. In particular, since the colloid-forming agent used for colloid formation is oxidatively removed, the agent exerts no influence on the catalytic activity of the fine noble-metal particles.
