A novel indanesulfamide compound, such as N-[(1S)-2,2,5,7-tetrafluoro-2,3-dihydro-1H-inden-1-yl]- sulfamide, N-[(1S)-2,2,4,7-tetrafluoro-2,3-dihydro-1H- inden-1-yl]sulfamide and (+)-N-(2,2,4,6,7- pentafluoro-2,3-dihydro-1H-inden-1-yl)sulfamide, or a pharmaceutically acceptable salt thereof has an effect of improving the severity (score) of an attack in a mouse kindling model and therefore can be expected to serve as a therapeutic agent for epilepsy.