To provide a novel cyclohexane derivative, a cyclohexane derivative is defined by the formula (I) or a pharmacologically acceptable salt thereof: ##STR1## (wherein R.sup.1 and R.sup.2 may be the same or different from each other and each represents hydrogen or lower alkyl; R.sup.3 represents optionally substituted aryl or optionally substituted heteroaryl; X represents oxygen or sulfur; and Y represents a group represented by the formula: ##STR2## or the like). The compound of the present invention is useful as a preventive and therapeutic agent for diseases against which a potassium channel opening action is efficacious.