In electroencephalography in daily living environments, and to estimate the cause of failures by determining failure has occurred in any source in which electrodes of the plurality of electrodes, to realize the electroencephalogram measurement stable easily. When the user wears the electroencephalogram measurement section for measuring an electroencephalogram signal, a frequency analyzer for analyzing each set of the measurement electrode and reference electrode, the frequency power of the EEG signal, EEG measurement system frequency power were analyzed by comparison with a first threshold, a fault electrode determining unit to determine whether the poor mounting state of each electrode is good, and the defect number of electrodes is determined that the mounted state is bad, and a plurality of electrodes is stored in advance and and a failure factor estimating unit for referring to the location of, and determine the position and trouble electrode is in contact with the user, to estimate the bad factor mounting state of the electrode with reference to the failure pattern. Position and electrode failure and the number of defects electrode mounted state is bad comes into contact with the user, the failure pattern is in association with the bad factors mounting state of the electrode.日常生活環境下での脳波計測において、複数の電極のうちどの電極でどのような要因で不具合が発生したかを判定して不具合要因を推定し、簡易に安定した脳波計測を実現する。脳波計測システムは、脳波信号を計測する脳波計測部をユーザが装着した際に、脳波信号の周波数パワーを、基準電極と計測電極との組ごとに解析する周波数解析部と、解析された周波数パワーと第1の閾値との比較により、電極ごとの装着状態が良いか悪いかを判定する不具合電極判定部と、装着状態が悪いと判定された不具合電極数と、予め記憶されている複数の電極の位置を参照して、不具合電極がユーザに接触する位置とを決定し、不具合パターンを参照して電極の装着状態が悪い要因を推定する不具合要因推定部とを備えている。不具合パターンは、装着状態が悪い不具合電極の数及び不具合電極がユーザに接触する位置と、電極の装着状態が悪い要因とを対応付けている。
