To provide an animal ectoparasiticide having excellent effects on animal ectoparasites.

The animal ectoparasiticide including a hydrazide compound represented by formula (1) [R3 is 1-6C alkyl which may be replaced with a halogen atom or the like; R5 is a 1-12C chain hydrocarbon group which may be replaced with a group selected from a group E1 or the like; R6 is a 1-12C chain hydrocarbon group which may be replaced with a group selected from a group E1 or the like; R9 is a 1-12C chain hydrocarbon group which may be replaced with a group selected from a group E1 or the like; R10 is a 1-12C chain hydrocarbon group which may be replaced with a group selected from a group E1 or the like] as an active ingredient exhibits excellent control effects on animal ectoparasites.