A new combustion pressure sensor capable of measuring the combustion pressure in an engine cylinder has been developed. This combustion pressure sensor has been used for control of the advanced lean combustion engine in TOYOTA 1992 model (Oct. 1992). The control system is useful for improvement of energy consumption efficiency and reduction of emissions from commercial cars. The successfully designed combustion pressure sensor has excellent features of low impedance and good linearity. It has been realized with the smallest number of components and reasonable cost.This paper describes the principle, structure and basic characteristics of the combustion pressure sensor.