We investigate brain potentials related to the abandonment of the motor intention prior to movement in human volitional finger movement. Subjects are instructed to conduct a point-to-point finger reaching movement with the right index finger. The time to begin this movement is indicated with a clock making one revolution in 4 s. The time at which the clock hand passes the 3 o'clock position is adopted as the go-signal in the go task. In the series of trials, the pre-stop task is conducted with a red light-emitting diode stop-signal presented randomly at 0.1, 0.2, 0.3, 0.4, or 0.5 s before the go-signal. Cerebral potentials at the scalp are recorded using a 20-channel electroencephalography (EEG) system. In the go task without the stop-signal, clear movement-related cortical potentials are observed. In the pre-stop task with the stop-signal, the subjects are able to inhibit finger movement. A positive EEG potential distributed at the midline fronto-central scalp at 300-500 ms after the go-signal is observed only in the pre-stop task. This result suggests that the observed positive component is associated with the interruption of motor intention, as well as the revision of motor planning, in the motor cortices prior to the movement.