A brain electrode system comprises: a brain electrode body which is placed in the cranium and has an electrode which detects a brain wave signal and a first coil through which an electric current corresponding to the brain wave signal flows and a communication unit which is disposed on the scalp, has a second coil which magnetically connects with the first coil and in which an induced electromotive force occurs due to a change in the current that flows through the first coil and receives the brain wave signal with the second coil.