Intake air flow rate measuring device

An intake air flow rate measuring device that is inserted into an attachment hole of an intake air duct introducing an intake air into an engine, the intake air flow rate measuring device measuring a flow rate of the intake air flowing through the intake air duct, the intake air flow rate measuring device comprising:

• a flange that is disposed outside of the intake air duct to cover the attachment hole;
• a casing that extends in both the attachment hole and the intake air duct;
• a flow rate sensor that is disposed in the casing to measure a flow rate of the intake air flowing through the intake air duct;
• a humidity sensing element that is disposed in the casing to measure a humidity of the intake air flowing through the intake air duct;
• an element terminal that is positioned only inside the intake air duct and is electrically connected to the humidity sensing element;
• and
• a humidity terminal that passes through the flange, wherein
• the humidity terminal is positioned spaced away from the element terminal,
• an electric connector is disposed between the humidity terminal and the element terminal to electrically connect the humidity terminal to the element terminal,
• heat is less likely to transfer through the electric connector as compared to the humidity terminal and the element terminal,
• a portion of the casing between the element terminal and the humidity terminal is defined as a suppressing portion, and a cross-section of the suppressing portion is defined as a suppressing portion cross-section, and
• an end portion of the casing close to the flange is defined as a base portion, and a cross-section of the base portion is defined as a base portion cross-section, wherein
• the suppressing portion cross-section is set to be smaller than the base portion cross-section.