A plant disease controlling composition containing a pyridazine compound represented by formula (I):wherein R1 represents a chlorine atom, a bromine atom, a cyano group, or a methyl group, and R2 represents a hydrogen atom or a fluorine atom andat least one carboxamide compound selected from the group consisting of bixafen, isopyrazam, boscalid, fluopyram, fluxapyroxad, sedaxane, penflufen, flutolanil, mepronil, carboxin, thifluzamide, penthiopyrad, and furametpyr.
