PHYSICAL QUANTITY DETECTOR

To provide a physical quantity detector with which it is possible to reduce dust flowing into a second sub-passage branched from a first sub-passage and improve resistance to contamination.SOLUTION: Provided is a physical quantity detector 20 for detecting physical quantity of gas. A measurement unit 213 includes a first sub-passage 234a extending along the center axis of a main passage from an inlet 231 and leading to a first outlet 232, a second sub-passage 234b branched from the first sub-passage 234a toward a flange 211 and leading to a second outlet 233, and a rectification surface 227. The rectification surface 227 includes an upstream rectification surface 227a provided so as to get close to the flange 211 from an upstream end face 228 to a downstream side of the main passage, and a downstream rectification surface 227b provided downstream of the main passage from the upstream rectification surface 227a and extending up to a downstream end face 224 along the center axis of the main passage.SELECTED DRAWING: Figure 3 【課題】第１副通路から分岐した第２副通路に流入する塵埃を減少させ、耐汚損性を向上させることが可能な物理量検出装置を提供する。【解決手段】気体の物理量を検出する物理量検出装置２０。計測部２１３は、入口２３１から主通路の中心軸に沿って延びて第１出口２３２に至る第１副通路２３４ａと、第１副通路２３４ａからフランジ２１１へ向けて分岐して第２出口２３３に至る第２副通路２３４ｂと、整流面２２７と、を有する。整流面２２７は、上流端面２２８から主通路の下流側へ向けてフランジ２１１に近づくように設けられた上流整流面２２７ａと、上流整流面２２７ａよりも主通路の下流側に設けられ下流端面２２４まで主通路の中心軸に沿って延びる下流整流面２２７ｂと、を有する。【選択図】図３