A sensor SA has a flow sensor that measures a flow rate of intake air in a measurement flow path. The flow sensor has a film-shaped sensor film portion overlapped on a substrate front surface of a sensor substrate. The sensor film portion has a heat generating resistor that heats the sensor film portion and a temperature measuring resistor that measures a temperature of the sensor film portion. The heat generating resistor and the temperature measuring resistor are arranged in a depth direction Z along the substrate front surface of the sensor substrate. A length dimension LM1 of an upstream temperature measuring resistor is equal to or larger than a length dimension LM2 of a downstream temperature measuring resistor.