Microparticle sensor

A particulate sensor attached to a pipe having electrical conductivity, and adapted to detect the amount of particulates in gas flowing through the pipe, comprising a sensor unit, wherein

• the sensor unit comprises
• an ion generation section for generating ions,
• an electric charge section for electrically charging at least portion of the particulates in the gas which contains the particulates, by use of the ions,
• a capture section for trapping at least portion of the ions not used for electrically charging the particulates, and
• a sensor ground section connected to the capture section and having a first floating potential corresponding to the amount of the ions trapped by the capture section;
• the sensor unit can detect the amount of the particulates in the gas on the basis of electric potential of the sensor ground section;
• and
• the sensor ground section is covered with insulating ceramic at that outer portion of the sensor unit which comes into contact with the gas.