An object of the present invention is to provide a therapeutic agent or prophylactic agent for Alzheimer's disease, which has an effect to inhibit or delay the progress of Alzheimer's disease and exhibits a long-lasting therapeutic effect on Alzheimer's disease even when used for a long period of time. The present invention provides a therapeutic agent or prophylactic agent for Alzheimer's disease, said agent comprising as an effective ingredient a cyclohexane derivative exemplified by the formula below, or a pharmaceutically acceptable salt thereof or a prodrug thereof.
