The present invention provides a composition for controlling plant diseases having an excellent control efficacy on plant diseases. A composition for controlling plant diseases comprising a carboxylic acid compound represented by a formula (I): wherein each of symbols are the same as defined in the Description; or salts thereof and one or more kinds of azole compounds selected from the group (A) consisting of tebuconazole, difenoconazole, triticonazole, imazalil, triadimenol, fluquinconazole, prochloraz, prothioconazole, diniconazole, diniconazole M, cyproconazole, tetraconazole, ipconazole, triforine, pyrifenox, fenarimol, nuarimol, oxpoconazole fumarate, pefurazoate, triflumizole, azaconazole, bitertanol, bromuconazole, epoxiconazole, fenbuconazole, flusilazole, flutriafol, hexaconazole, imibenconazole, myclobutanil, penconazole, propiconazole, simeconazole, triadimefon and metconazole, shows an excellent controlling efficacy on plant diseases.