Disclosed is an agent for improving learning and/or memory, which is useful for therapy of dementia accompanying disorder of memory due to a cerebrovascular disease, neurodegenerative disease such as Alzheimer's disease, endocrine disease, nutritional or metabolic disorder, infectious disease, drug addiction or the like. The agent for improving learning and/or memory according to the present invention comprises as an effective ingredient an isoquinoline derivative having a specific structure, such as (4aR, 12aR)-2-methyl-4a-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a-octahydro-quinoline[2,3-g]isoquinoline or a pharmaceutically acceptable salt thereof.