<;P>;PROBLEM TO BE SOLVED: To provide a flea-controlling agent that exhibits enhanced controlling effects on various kinds of fleas, for example, a cat flea parasitic on house pets, and is safe and available inexpensively. <;P>;SOLUTION: The flea-controlling agent comprises pyrethrum extracts (component (a)) and N-(2-ethylhexyl)-bicyclo[2,2,1]-hept-5-ene-2,3-dicarboxy imide (component (b)) with the mass ratio of total pyrethrin of the component (a) to the component (b) of 1:0.5 to 1:4. Preferably, the Exo type/(Exo type + Endo type) ratio of the component (b) is 0.3-0.7. <;P>;COPYRIGHT: (C)2010,JPO&INPIT