To obtain a preservative which has an activity, e.g. ingestion inhibitory effect, repelling and inhibitory effect or insecticidal effect, against insect pests of timbers and shows antimicrobial, fungicidal or antiseptic effect by making the reservative include a component selected from among a hiba neutral oil, a hinoki oil and a p-oxybenzoic ester as an active ingredient.

This preservative is obtained by including at least one kind among (A) a hiba neutral oil (a residue freed of acidic oils from a hiba oil), (B) a hinoki oil (e.g. an oil obtained by steam distillation of sawdust of hinoki scrap woods or the like) and (C) a p-oxybenzoic ester (e.g. n-propyl p- oxybenzoate or the like) as active ingredients. It is favorable that the above preservative contains the components A, B and C in amounts of 0.01-90 wt.%, respectively. Further, when (D) boric acid and/or boron in addition to the above components are added in amounts of 0.01-90 wt.%, respectively, the activity, e.g. ingestion inhibitory effect or the like against insect pests of timbers, is more increased and antimicrobial fungicidal effect or the like can also be enhanced.