Thermal Flow Meter with a Case Having a Resin Housing which Supports a Circuit Package

A thermal flow meter comprising:

• a bypass passage into which a measurement target gas flowing through a main passage flows;
• a circuit package which includes an air flow sensing portion for measuring a flow rate by performing heat transfer with the measurement target gas flowing through the bypass passage, a processing unit for controlling the air flow sensing portion, and a temperature detecting portion including a temperature detection element for detecting a temperature of the measurement target gas;
• and
• a case which includes an external terminal for outputting an electric signal representing the flow rate and an electric signal representing a temperature of the measurement target gas and supports the circuit package, wherein
• the case includes a resin housing which supports the circuit package,
• the circuit package includes a circuit package body that is molded by a resin and the circuit package is configured to envelope the processing unit and the temperature detecting portion with the resin,
• the circuit package includes a protrusion protruding to the main passage by penetrating through the wall of the bypass passage, and the temperature detection element is buried in the protrusion, and at least a leading end portion of the protrusion is exposed in the main passage.