The purpose of the present invention is to provide: a virus inactivating agent that exhibits an effect at an amount that does not cause skin irritation; and an external skin preparation composition containing said virus inactivating agent. The present invention relates to: a virus inactivating agent containing, as an effective component thereof, at least one selected from mint oil, eucalyptus oil,rosemary oil, sage oil, tea tree oil, shell ginger oil, peppermint oil, lemongrass oil, cajeputi oil, niaouli cineole oil, lime oil, lemon oil, lemon verbena oil, St. John's wort oil, ravintsara oil,rosewood oil, Melissa/lemon balm oil, myrrh oil, mandarin oil, vetiver oil, frankincense oil, citronella oil, cardamom oil, Angelica oil, and cationized starch; and an external skin preparation composition containing the same.