To acquire electroencephalogram of high resolution with a smaller number of electrodes than usual.An electroencephalogram measuring electrode (110) to be attached on a scalp of a subject to acquire an electroencephalogram signal of a subject, and a brain wave measuring electrode (110) using an electroencephalogram signal acquired from a plurality of electroencephalogram measuring electrodes And an electroencephalogram generation unit (150) for generating an electroencephalogram at a place where the electroencephalogram measurement electrode is attached and an electroencephalogram at a place where the electroencephalogram measurement electrode is not attached.【課題】通常よりも少ない数の電極で高分解能の脳波を取得する。【解決手段】被検者の脳波信号を取得するために被検者の頭皮上に取り付ける複数の脳波測定電極（１１０）と、複数の脳波測定電極から取得された脳波信号を用いて脳波測定電極が取り付けられている場所の脳波および脳波測定電極が取り付けられていない場所の脳波を生成する脳波生成部（１５０）と、を有する。
