The present invention relates to a novel dihydroxyphenyl-based stereoisomer having Hsp90-inhibiting activity and a pharmaceutical composition or a health functional food comprising the same. The stereoisomer can be confirmed to have an excellent Hsp90 inhibitory effect of 30 times or more, which is unpredictable from a racemic mixture, thereby being usefully used as a pharmaceutical composition for preventing or treating Hsp90-mediated disease selected from a group consisting of cancerous disease, neurodegenerative disease, and viral infection or used as a health functional food for preventing or alleviating Hsp90-mediated disease selected from the same.COPYRIGHT KIPO 2019