Physical quantity detection device

A physical quantity detection device for detecting a physical quantity of a measurement target gas passing through a main passage, the physical quantity detection device comprising:

• a housing inserted into the main passage;
• a cover fixed to the housing to constitute a bypass passage into which a part of the measurement target gas flows from the main passage in cooperation with the housing;
• a circuit substrate accommodated in the housing to be exposed into the bypass passage;
• a sensor element attached to the circuit substrate to detect a flow rate of the measurement target gas in the bypass passage;
• a connection wire electrically connecting the sensor element to the circuit substrate;
• and
• a synthetic resin material applied to a connected portion of the sensor element including the connection wire and the circuit substrate and cured to seal the connected portion,
• wherein the cover includes a protrusion protruding into the bypass passage to cover at least a part of the synthetic resin material.