Provided is a thermal flow meter including a measurement tube made of resin having an inlet and an outlet, and an internal flow passage extending along an axis, a sensor substrate having a heating resistance wire and temperature detecting resistance wires formed on a detection surface along the axis, and a reinforcing plate. The sensor substrate is bonded to the measurement tube along the axis with an adhesive, and the reinforcing plate is bonded to the measurement tube along the axis with the adhesive with the internal flow passage interposed between the sensor substrate and the reinforcing plate.