PROBLEM TO BE SOLVED: To provide a biological body information detector or the like being capable of continuously detecting biological body information while reducing a load at the time of mounting for a long period of time.SOLUTION: A biological body information detector includes: a band section 10; a case section 30 mounted on the band section 10; a sensor section provided on the case section 30; and a processing section being provided on the case section 30 and detecting biological body information on the basis of a detection signal from the sensor section. The band section 10 has an inner surface 11 having a first curved shape at a side facing an inspection object at the time of mounting. The case section 30 has an outer surface 31 having a second curved shape facing the inner surface 11 of the band section 10.【課題】長時間装着時の負担を軽減しながら連続した生体情報の検出が可能な生体情報検出装置等の提供。【解決手段】生体情報検出装置は、バンド部10と、バンド部10に取り付けられるケース部30と、ケース部30に設けられるセンサー部と、ケース部30に設けられ、センサー部からの検出信号に基づいて生体情報を検出する処理部を含む。バンド部10は、装着時に被検体に対向する側に第1曲面形状の内面11を有し、ケース部30は、バンド部10の内面11に対向する第2曲面形状の外面31を有する。【選択図】図6