The present invention is directed to KIAA1199, which is a novel factor involved in decomposition of hyaluronic acid, and to use thereof. More specifically, the invention is directed to a hyaluronic acid decomposition-promoting agent containing the KIAA1199 gene and a protein encoded by the gene； to a hyaluronic acid decomposition-inhibiting agent characterized by inhibiting the activity or expression thereof (including an siRNA or a monoclonal antibody)； and to a method for screening a novel hyaluronic acid decomposition-controlling agent, in which the method contains employing the expression of KIAA1199 as an index.
