PROBLEM TO BE SOLVED: To provide a pressure measurement chamber which is capable of suppressing occurrence of unintended wrinkles in a diaphragm membrane and is unlikely to cause decrease in the pressure measurement range.SOLUTION: The pressure measurement chamber comprises: a housing 101 including a first hard frame body 111 and a second hard frame body 112 joined opposingly to each other so as to form a cavity inside； a dome-shaped diaphragm body 121 interposed between the first frame body 111 and the second frame body 112； and a diaphragm membrane 102 with a rib 122 provided on a circumference of the membrane body 121. The rib 122 includes a positioning portion for positioning relative to the housing 101. At least one of a first flange portion 114 and a second flange portion 118 includes a guide portion for positioning of each other and a positioned portion for forming a complementary structure with the positioning portion. The positioning portion is for example a positioning protruded portion 132 which is provided on an outer edge of the rib 122 such that the rib width is different from that of other portions of the rib.SELECTED DRAWING: Figure 1【課題】ダイアフラム膜の意図しないしわの発生を抑え、圧力測定範囲の減少が生じにくい圧力測定用チャンバを実現できるようにする。【解決手段】圧力測定用チャンバは、内部に空洞を設けるように互いに向かい合わせて接続された硬質の第１の枠体１１１と第２の枠体１１２とを含むハウジング１０１と、第１の枠体１１１と第２の枠体１１２との間に配置されたドーム状の膜本体１２１と、膜本体１２１の周囲に設けられたリブ１２２とを有するダイアフラム膜１０２とを備えている。リブ１２２は、ハウジング１０１に対する位置決めを行う位置決め部を有し、第１の鍔部１１４及び第２の鍔部１１８の少なくとも一方は、互いの位置決めを行うガイド部と、位置決め部と相補的な相補構造をなす被位置決め部とを有している。位置決め部は、例えば、リブ幅がリブの他の部分と異なるようにリブ１２２の外縁に設けられた位置決め凸部１３２である。【選択図】図１
