Provided is a material that modulates Period gene expression effectively and can be used in a wide range of applications. The Period gene expression modulator contains as an active ingredient at least one ingredient selected from a group comprising arnica extract, Japanese spatterdock extract, tea extract, Japanese pepper extract, juniper oil, cedar oil, lavender oil, clove bud oil, cypress oil, rose oil, ylang ylang oil, galbanum oil, petitgrain oil, pepper oil, thyme oil, basil oil, and beta caryophyllene.本發明之課題在於提供一種可應用於廣泛用途且有效地調節Period基因表現之物質。本發明係關於一種Period基因表現調節劑，其含有選自由山金車萃取物、日本萍蓬草萃取物、紅茶萃取物、山椒萃取物、杜松子油、雪松油、薰衣草油、丁香花苞油、絲柏油、玫瑰油、伊蘭油、白松香油、苦橙葉油、胡椒油、麝香草油、羅勒油及β-丁香烯所組成之群中之1種以上作為有效成分。
