At least the brain wave measuring electrode 33 where it possesses 2 probe applied parts 61a, the light transmission probe 12 which irradiates light to probe applied part 61a from the Tip, or, the light absorbent probe 13 which absorbs light being interposed light from the Tip, the optical living body measurement holder 60 which is installed in the head of the suffering inspection person and, possesses 1 electrode applied parts 161a at least, detects the potential difference of reference electrode 32 in electrode applied part 161a being interposed, being the holder set which has with the electroencephalograph holder 160 which is installed in the head of the suffering inspection person, as for optical living body measurement holder 60, unidirectionalBasic section 62 of the rectilinear condition which extends and, it has with the branches 61 of the rectilinear condition 2 where it extends bidirectionally differs from unidirectional at least, basic section 162 of the rectilinear condition which extends unidirectionally and, the two directions at least try electroencephalograph holder 160, to have with the branches 161 of the rectilinear condition 1 where it extends to converse direction.少なくとも2個のプローブ装着部61aを有し、プローブ装着部61aに先端から光を照射する送光プローブ12、又は、先端から光を受光する受光プローブ13が挿入されて、被検者の頭部に装着される光生体測定ホルダ60と、少なくとも1個の電極装着部161aを有し、電極装着部161aに基準電極32との電位差を検出する脳波測定電極33が挿入されて、被検者の頭部に装着される脳波計ホルダ160とを備えるホルダセットであって、光生体測定ホルダ60は、第一方向に伸びた直線状の基幹部62と、第一方向と異なる第二方向に伸びた少なくとも2本の直線状の枝部61とを備え、脳波計ホルダ160は、第一方向に伸びた直線状の基幹部162と、第二方向と逆方向に伸びた少なくとも1本の直線状の枝部161とを備えるようにする。
