The present invention relates to a brain stimulating device and, particularly, relates to a brain stimulating device comprising: a brainwave measurement unit for outputting a brainwave signal； and a stimulation unit for applying spindle-like stimulation to a brain in accordance with the generation of slow oscillation included in the brainwave signal. The brain stimulating device according to the present invention can reinforce memory or reduce memory deterioration due to dementia. Also, the brain stimulating device according to the present invention can reinforce hippocampus-dependent memory. Further, a portable device according to the present invention can control and monitor the brain stimulating device. Moreover, a method for assessing the performance of the brain stimulating device according to the present invention can assess the performance of the brain stimulating device.
