Provided is a novel amino acid derivative having excellent analgesic effect. The amino acid derivatives is a novel compound exhibiting excellent analgesic effect not only on nociceptive pain mode animals but also on neuropathic pain mode animals, and is useful as a drug for treating various pain conditions represented as acute or chronic pain or neuropathic pain.本發明提供具有優異鎮痛作用之新穎胺基酸衍生物。本發明之胺基酸衍生物係不僅對於侵害接受性疼痛模式動物,對於神經因性疼痛模式動物亦呈現優異鎮痛作用之新穎化合物,非常有用於作為呈現為急性或慢性疼痛或神經因性疼痛之各種疼痛性疾患的治療用藥劑。