Thienocycloheptapyridazine compounds represented by general formula (I), wherein R represents hydrogen, halogen or C 1·4 alkyl, Ar represents aryl or heteroaryl which may have at least one substituent selected from among halogen, C 1·4 alkyl, C 1·4 alkoxy, nitro, amino. hydroxy, trifluoromethyl and C 2·5 alkanoyl, and a bond ---- between the 6a-position and the 7-position represents a single or double bond are disclosed. The compounds are useful as an anti-anxiety agent, amnesia treating agent, brain function activating agent or dementia treating agent.