A plant disease controlling composition containing a pyridazine compound represented by formula (I):whereinR1 represents a chlorine atom, a bromine atom, a cyano group or a methyl group, and R2 represents a hydrogen atom or a fluorine atom, and at least one azole compound selected from Group (A).Group (A): Group consisting of propiconazole, prothioconazole, triadimenol, prochloraz, penconazole, tebuconazole, flusilazole, diniconazole, bromuconazole, epoxiconazole, difenoconazole, cyproconazole, metconazole, triflumizole, tetraconazole, myclobutanil, fenbuconazole, hexaconazole, fluquinconazole, triticonazole, bitertanol, imazalil, ipconazole, simeconazole and flutriafol.