The present invention provides a prophylactic or therapeutic agent for Alzheimer's disease (AD) containing a combination of two or more compounds selected from the group consisting of compounds shown by compound Nos. 1 to 130. Since these compounds are existing drugs that have already been confirmed actually for safety and pharmacokinetics in human, they can be a means for a pre-emptive treatment of people at risk of AD and in a stage before developing mild cognitive impairment (MCI).