The present invention provides a brain function measuring apparatus 1 which uses a magnetic generator 3 and a magnetic sensor 4. The magnetic generator 3 is arranged at a deep portion of the brain 2 such as in the oral or nasal 15 cavity and may be a neodymium magnet. The magnetic sensor 4 is arranged on the scalp 7 and senses the magnetic field generated by the magnetic generator. The magnetic sensor may be a three dimensional magnetic sensor and there may be a plurality of magnetic sensors. The magnetic sensor senses the magnetic field after it has passed through the brain of the subject which is relevant to the brain activity of the subject.
