Problem to be Solved An agent for ameliorating chronic kidney disease which is not an existing symptomatic therapeutic drug for chronic kidney disease, and which can increase the eGFR value and can improve renal function per se is provided. Solution An agent for ameliorating and/or preventing chronic kidney disease containing 5-aminolevulinic acid (ALA) or a derivative thereof, or a salt thereof as an active ingredient is prepared. Preferably, a metal-containing compound such as sodium ferrous citrate is contained in these ALAs. As the above-mentioned ALAs, ALA； various esters such as ALA methylester, ALA ethylester, ALA propylester, ALA butylester, and ALA pentylester； and hydrochlorides, phosphates, and sulfates, and the like of these ALA esters can be preferably exemplified.
