A method for remarkably enhancing plant disease controlling effects, and a method for controlling plant diseases are provided. A method for enhancing plant disease controlling effects of an aryl phenyl ketone fungicide includes using an aryl phenyl ketone fungicide as a component (a) in combination with at least one component (b) selected from the group consisting of a nonionic surfactant, an anionic surfactant, a cationic surfactant, a vegetable oil, a paraffin, a resin and a terpene.