The invention provides an excellent novel analgesic which acts on a nociceptin receptor to exhibit a wide range of the analgesic effect for example on a chronic pain as well as an allodynia accompanied with a herpes zoster.The invention relates to a nociceptin receptor agonist comprising as an active ingredient a compound represented by Formula (I) or a salt thereof: ##STR00001## wherein R.sup.1 represents a hydrogen atom or alkyl; A.sup.1 and A.sup.2 are the same or different and each represents a single bond or a divalent aliphatic hydrocarbon group; Q represents a single bond, cycloalkylene group, phenylene group or a divalent heterocyclic group; R.sup.2A and R.sup.2B are the same or different and each represents a hydrogen atom or alkyl; R.sup.3 represents an optionally substituted phenyl group or heterocyclic group; R.sup.4 and R.sup.5 are the same or different and each represents a hydrogen atom, alkyl, alkoxy, aralkyloxy, halogen, nitro, hydroxy, alkoxycarbonyl, --NR.sup.6R.sup.7 and the like.