A very quick response air mass flowmeter for accurate measurement of intake air in internal combustion engines was developed. This flowmeter consists of a disk type anode surrounded by two coaxial cylinders which serve as the first and second cathodes, respectively, Steady state flow tests show this flowmeter has sufficient accuracy, linearity, and directivity and no hysteresis was observed. The effects of temperature, pressure, and humidity of the air were studied. For pulsating air flow this flowmeter showed excellent dynamic response. Furthermore this meter succeeded in measuring the intake air flow rate of a single cylinder spark ignition engine under firing conditions, Therefore this flowmeter is very useful not only for analyzing the transient characteristics of internal combustion engines, but also for the accurate control of the fuel injection systems of gasoline engines.