An object of the present invention is to develop and provide a new drug that has an activity against canine filariasis having concerns about the possibility of developing resistance to addictive agents due to long-term use of canine filariasis control agents and that can be used to treat infections caused by canine filariasis. The present invention provides a benzimidazole compound represented by general formula (1):




wherein R, Y1, Y2, Y3, and Y4 represent a hydrogen atom or the like, and X represents an alkynyl group or the like, or a salt thereof. The present invention also provides a canine filariasis control agent for an animal, containing the same as an active ingredient, and a method of using the same.