We have developed a brain-machine interface (BMI) by using a method based on near-infrared spectroscopy. We call our interface ldquoOptical-BMIrdquo. It functions as a practical, unrestrictive, non-invasive brain-switch without the need for large equipment. During an experiment with the prototype system, an operator manipulated external electrically controlled equipment while we measured the corresponding spatiotemporal changes in the hemoglobin concentration in the blood flowing through his or her pre-frontal cortex by using a probe cap with 22 measurement points.