PROBLEM TO BE SOLVED: To provide a manufacturing method of a medicine containing an amino acid derivative having excellent analgesic action as an active ingredient and a derivative of the same.SOLUTION: The medicine contains the amino acid derivatives having the excellent analgesic action, such as a calcium salt of Nα-[3-(2-fluorophenyl)acryloyl]-L-tryptophan or a hydrate of the calcium salt or the like. The medicine shows the excellent analgesic action not only to a nociceptive pain model animal but also to a neuropathic pain model animal and is very useful as an anodyne or the like for treating various kinds of painful diseases showing acute or chronic pain and neuropathic pain.
