Temperature and humidity sensor

Abstract

In order to provide a temperature and humidity sensor with improved reliability, the temperature and humidity sensor in which all or part of a case of the temperature and humidity sensor is inserted into a main duct for causing gas to pass through and which detects humidity of the gas, includes: a first sub-passage configured as a part of the case, a part of the gas passing through the main duct flowing in substantially the same direction as a flow in the main duct; a throttle section provided between an inlet and an outlet of the first sub-passage and on an inner surface of the first sub-passage, the throttle section having a throttle whose cross-sectional area is smaller than an average cross-sectional area of the entire first sub-passage; and a second sub-passage which connects an upstream side and a downstream side of the throttle section and is different from the first sub-passage. The first sub-passage and an inlet and an outlet of the second sub-passage are connected via respective connection ports, and the connection port between the inlet of the second sub-passage and the first sub-passage or the connection port between the outlet of the second sub-passage and the first sub-passage is provided on a side where a throttle is not provided when viewed from an axis in an upstream and downstream direction of the flow in the first sub-passage.