PROBLEM TO BE SOLVED: To provide a technology and a device for suppressing the occurrence of a measurement error, even when a subject of pulse oximetry is a newborn.SOLUTION: A photosensor includes a rod-like gripping body 14 that is provided with one of a light-emitting element 2 and a light-receiving element 3 and that is gripped by a subject, and a holding member 16 that holds a part of the subject's hand between itself and the gripping body 14. The other one of the light-emitting element 2 and the light-receiving element 3 is arranged in the holding member 16.【課題】パルスオキシメトリの被検者が新生児である場合においても、測定誤差の発生を抑制する技術、装置を提供する。【解決手段】発光素子２と受光素子３の一方が設けられ、被検者に把持される棒状の把持体１４と、前記把持体１４との間に前記被検者の手の一部を挟持する挟持部材１６とを備えており、前記発光素子２と前記受光素子３の他方は、前記挟持部材１６に配置されている。【選択図】図３
