A method and an instrument for exterminating vermin whereby specific vermin can be effectively exterminated without damaging other plants or animals. The instrument for exterminating vermin comprises a copper-zinc alloy fiber 12 produced by fiberizing a copper-zinc alloy. The copper-zinc alloy fiber 12 is housed in a bag-shaped net body 14 and disposed in water 16 inhabited by the vermin to be exterminated such as Pomacea canaliculata or Limnoperna fortunei. Thus, Pomacea canaliculata can be exterminated by copper ion and zinc ion eluted into water from the copper-zinc alloy fiber 12.
