The antignawing activity of the steam distillate ofThujopsis dolabrata S. et. Z. var.hondai sawdust against mice was evaluated using a wire-dipping method. This method is suitable for measuring repellent activities of chemicals and plant-derived materials. The steam distillate of theThujopsis sawdust was shown to have potent antignawing activity. Three terpenoid compounds with antignawing activity were isolated from the steam distillate of theThujopsis sawdust: thujopsene, carvacrol, and-thujaplicine. Carvacrol exhibited the most potent repellent activity. As a naturally occurring repellent, carvacrol could be useful as new preventive agent against various kinds of damage caused by rodents.