PROBLEM TO BE SOLVED: To provide a light projecting/receiving system that is light in weight and compact and performs illumination having a stable luminance center of gravity, and an optical biological information measuring device for performing measurement of high reproducibility by providing the light projecting/receiving system.SOLUTION: This light projecting/receiving system 10 includes a light projection fiber bundle 2 that guides the light LW coming from a xenon tube 1 side from an incoming port 2p to an outgoing port 2q, and emits it to a living body 9 side, and light receiving fiber bundles 3 that guide the lights LA and LB returning from the living body 9 side from incoming ports 3pA and 3pB to outgoing ports 3qA and 3qB, and emit them to the side of two-wavelength light receiving elements 5A and 5B. The direction corresponding to the largest direction of luminance unevenness of the xenon tube 1 is assumed to be a main direction M, and the orthogonal direction to the main direction M is assumed to be a sub direction S. At this time, the outgoing port 2q of the light projection fiber bundle 2 and the incoming ports 3pA and 3pB of the light receiving fiber bundles 3A and 3B are positioned adjacently to each other in the sub direction S, the incoming port 2p and outgoing port 2q of the light projection fiber bundle 2 have a surface shape longer in the main direction M than in the sub direction S, and the incoming port 2p and outgoing port 2q of the light projection fiber bundle 2 have the same strand array in the sub direction S.COPYRIGHT: (C)2011,JPO&INPIT【課題】軽量・コンパクトでありながら輝度重心の安定した照明が可能な投受光系と、その投受光系を備えることにより再現性の高い測定が可能な光学的生体情報測定装置を提供する。【解決手段】投受光系10は、キセノン管1側からの光LWを入射口2pから出射口2qへと導光して生体9側へ出射する投光ファイバー束2と、生体9側から戻ってきた光LA,LBを入射口3pA,3pBから出射口3qA,3qBへと導光して2波長受光素子5A,5B側へ出射する受光ファイバー束3と、を備える。キセノン管1の輝度ムラが最も大きい方向に対応する方向を主方向Mとし、その主方向Mに対して対応する直交方向を副方向Sとするとき、投光ファイバー束2の出射口2qと受光ファイバー束3A,3Bの入射口3pA,3pBとが副方向Sに隣り合って位置し、投光ファイバー束2の入射口2p及び出射口2qが副方向Sよりも主方向Mに長い面形状を有し、投光ファイバー束2が入射口2pと出射口
