To easily maintain the state of attachment onto a biological surface to be constant, and to accurately measure a pulse wave.SOLUTION: A pulse wave sensor 1 comprises: an attachment 12 having an opening to be pressed against a living body surface S1 and a sensor chamber 11 inside； a pressure sensor 14 which is displaced in accordance with a change in an internal pressure of the sensor chamber which changes in response to a pulsation of a living body when the attachment is pressed against the living body surface； a pulse wave detection unit which detects a pulse wave on the basis of the displacement of the pressure sensor； and a measuring state detection unit 17 which detects a measurement state of the pulse wave on the basis of the pressing state of the attachment pressed against the living body surface.SELECTED DRAWING: Figure 3【課題】生体表面に対する装着状態を一定の状態に維持し易く、脈波を精度良く測定すること。【解決手段】生体表面Ｓ１に押し当てられる開口部及び内部にセンサ室１１を有するアタッチメント部１２と、アタッチメント部が生体表面に押し当てられた際に、生体の脈動に対応して変化するセンサ室の内圧変化に応じて変位する圧力センサ１４と、圧力センサの変位に基づいて脈波を検出する脈波検出部と、生体表面に押し当てられたアタッチメント部の押し当て状態に基づいて、脈波の測定状態を検出する測定状態検出部１７と、を備える脈波センサ１を提供する。【選択図】図３
