An electroencephalogram interface system includes a biological signal detection section for detecting an electroencephalogram signal from a user and a control section for distinguishing a component of an event-related potential and causing a device to operate based on the distinguished event-related potential. An activation apparatus activates the control section and an output section for presenting a visual stimulation which flickers with a predetermined frequency based on a signal from the activation apparatus. The activation apparatus includes: a frequency analysis section for analyzing a frequency component of the electroencephalogram signal and detecting an intensity corresponding to the predetermined frequency and a determination section for comparing the detected intensity of the predetermined frequency and a predetermined threshold, and if the intensity of the predetermined frequency is equal to or greater than a predetermined threshold, activating the control section.
