The present invention aims to provide a medicine having a cognitive function improving effect and an anti-diabetes action. A phospholipid compound containing unsaturated fatty acid having a cyclopropane ring such as 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) and 8-(2-octylcyclopropyl)octanoic acid (DCP-OA) and the like, particularly 1,2-o-bis-[8-{2-(2-pentyl-cyclopropylmethyl)-cyclopropyl}-octanoyl]-sn-glycero-3-phosphatidylethanolamine (diDCP-LA-PE), has a cognitive function improving effect and an anti-diabetes action, and is useful as a medicine such as a therapeutic drug for dementia, a therapeutic drug for diabetes and the like.
