Provided are a therapeutic agent and a pharmaceutical composition exerting an excellent prophylactic or therapeutic effect on fibrosis and symptoms associated with fibrosis. The therapeutic agent for fibrosis comprises 4-[2-fluoro-4-[[[(2-phenylacetyl)amino]thioxomethyl]amino]-phenoxy]-7-methoxy-N-methyl-6-quinolinecarboxamide or a salt thereof as an active ingredient.