To input a selection based on a user's will into computers with high efficiency and high accuracy.SOLUTION: A computation processing unit (23) is capable of executing input determination processing for determining which photic stimulus a user focuses on based on photic stimulus visual evoked potentials included in a brain wave signal from a brain wave measurement unit (10), while causing a photic stimulus display unit (30) to display a plurality of photic stimuli blinking at mutually different blinking frequencies. The computation processing unit is capable of executing frequency setting processing for setting the blinking frequency on the basis of the brain wave signal. The computation processing unit is configured to, as the frequency setting processing: determine that the brain wave signal is steady at a prescribed level on the basis of the brain wave acquired by causing the brain waves to be measured in a non-blinking state of the photic stimulus； then acquire the brain wave signal acquired by further causing the brain wave to be measured in the non-blinking state of the photic stimulus； conduct a frequency analysis of the brain wave signal； select a plurality of frequencies which are included within a prescribed setting frequency band, have signal intensity equal to or less than a setting threshold, and are mutually at setting frequency intervals； and set these frequencies as a blinking frequency.SELECTED DRAWING: Figure 4【課題】使用者の意思による選択をコンピューターに高効率、高精度に入力する。【解決手段】演算処理部（２３）は、互いに異なる点滅周波数で点滅する複数の光刺激を光刺激表示部（３０）に表示させつつ、脳波測定部（１０）からの脳波信号に含まれる光刺激視覚誘発電位に基づき使用者がどの光刺激を注視していたかを判定する入力判定処理が実行可能である。演算処理部は、その点滅周波数を脳波信号に基づき設定する周波数設定処理が実行可能であり、演算処理部は周波数設定処理として、光刺激の非点滅状態にて脳波を測定させ取得した脳波信号に基づき当該脳波信号が所定レベルに安定したと判断した後、さらに光刺激の非点滅状態にて脳波を測定させて脳波信号を取得し、当該脳波信号を周波数解析し、所定の設定周波数帯内に含まれ、信号強度が設定閾値以下であって互いに設定周波数間隔を隔てた複数の周波数を選出し、これらを点滅周波数として設定する。【選択図】図４
