The present disclosure provides a flow rate measuring device including a flow rate detecting body, a humidity detecting body, and a base. The flow rate detecting body protrudes inside of an intake passage. The humidity detecting body protrudes inside of the intake passage at a position away from the flow rate detecting body. The base is connected to the flow rate detecting body and the humidity detecting body. The humidity detecting body holds a sensor chip that includes a humidity detecting element sensitive to the humidity of the intake air. A length, along a flow direction of the intake air, of an exposed portion of the humidity detecting body is defined as a referential length. The humidity detecting element exists within a range from an upstream end of the exposed portion of the humidity detecting body to a position of half the referential length.