PROBLEM TO BE SOLVED: To provide a kinesin inhibitor and a composition useful for alleviating and suppressing various pigmentation symptoms such as stains and freckles.SOLUTION: This invention provides a kinesin inhibitor or pigmentation inhibitor comprising rosmarinic acid or glycoside thereof (rosmarinic acid-4-O-galactoside, rosmarinic acid-4'-O-galactoside, rosmarinic acid-3-O-glucoside, rosmarinic acid-3'-O-glucoside, or rosmarinic acid-4-O-glucoside) as an active ingredient. Further, this invention provides various compositions comprising the kinesin inhibitor or pigmentation inhibitor (a pharmaceutical composition, a food and drink composition, or a cosmetic composition).【課題】キネシン抑制剤及び、シミやソバカスをはじめとする様々な色素沈着症状の緩和、抑制に有用な組成物の提供。【解決手段】ロスマリン酸又はその配糖体（ロスマリン酸-4-O-ガラクトシド、ロスマリン酸-4'-O-ガラクトシド、ロスマリン酸-3-O-グルコシド、ロスマリン酸-3'-O-グルコシド、ロスマリン酸-4-O-グルコシド）を有効成分として含有するキネシン抑制剤又は色素沈着抑制剤。更に、キネシン抑制剤又は色素沈着抑制剤を含有する各種組成物（医薬組成物、飲食品組成物、化粧料組成物）。【選択図】なし
