The purpose of the present invention is to provide a dosing technique for rifampicin, the technique being capable of long-term administration by enhancing the direct transfer of rifampicin to the brain and by suppressing the hepatic first-pass effect. This pharmaceutical composition for nasal administration, which contains, as an active ingredient, rifampicins selected from the group consisting of rifampicin, derivatives thereof, and salts thereof, and is used for the prevention or treatment of dementia, is capable of long-term administration by enhancing the direct transfer of rifampicin to the brain and suppressing the hepatic first-pass effect.
