In a biopsy needle having an inner needle having a sample collection portion and a hollow tubular outer needle that accommodates the inner needle, and in a photoacoustic measuring device having this type of biopsy needle, a light guide member such as an optical fiber is provided. It can be easily and accurately arranged. From the hollow tubular outer needle 50, the inner needle 60 that can move relative to the outer needle 50 in the tube axis direction and is disposed in the hollow portion of the outer needle 50, and can be punctured into the living body, In a biopsy needle having a concave sample collection part 62 cut inward from the inner needle peripheral surface 60a provided in a part distant from the rear end side, the inner needle is at least more than the sample collection part 62 of the inner needle 60 Outer grooves extending in the tube axis direction of the outer needle 50 are provided on the front end side and the rear end side, and the light guide member 16 is disposed in the outer grooves. Then, at least a part of the light guide member 16 is fixed by the fillers 65 and 66 filled in the outer groove.試料採取部を有する内針と、この内針を収容する中空管状の外針とを有する生検針において、また、この種の生検針を有する光音響計測装置において、光ファイバ等の導光部材を容易にかつ精度良く配設可能とする。中空管状の外針５０と、外針５０に対して管軸方向に相対移動可能にして外針５０の中空部内に配され、生体内に穿刺され得る内針６０と、内針６０の先端から後端側に離れた部分に設けられた、内針周面６０ａから内方に切り込んだ凹部状の試料採取部６２とを有する生検針において、内針６０の少なくとも試料採取部６２よりも内針先端側と後端側に、外針５０の管軸方向に延びる外溝を設け、この外溝内に導光部材１６を配置する。そして導光部材１６の少なくとも一部を、外溝内に充填された充填材６５、６６によって固定する。
