Provided is a plant disease control composition having a broad spectrum against various plant pathogens, and shows excellent controlling effects (synergistic controlling effects) which cannot be expected from a single component alone. The plant disease control composition comprises (Group a) at least one quinoline compound represented by the formula: (wherein R1, R2: an alkyl which may be substituted, an aryl which may be substituted, etc.; R3, R4: H, an alkyl which may be substituted, etc.; X: halogen, an alkyl which may be substituted, etc.; Y: halogen, alkyl, etc.; n: 0 to 4; m: 0 to 6) or a salt thereof, and at least one of fungicidal compounds selected from the group consisting of a Strobilurin series compound, a triazole series compound, etc., as effective ingredients.