Particulate matter detection device

A particulate matter detection device comprising:

• a plate-like element base material;
• a pair of measurement electrodes arranged in the element base material;
• characteristics measurement means for measuring electric characteristics between the pair of measurement electrodes;
• and particulate matter amount calculation means for calculating an amount of a particulate matter collected in and around the pair of measurement electrodes on the basis of a change amount of the electric characteristics measured by the characteristics measurement means,
• wherein the characteristics measurement means includes a voltage applying circuit which applies a voltage signal having a specific frequency to one measurement electrode of the pair of measurement electrodes, a current-voltage conversion circuit connected to the other measurement electrode of the pair of measurement electrodes, a detection circuit which decomposes an output of the current-voltage conversion circuit into orthogonal components by synchronous wave detection of two or more phases, to detect the output, and two or more calibration elements electrically connected to the voltage applying circuit and the current-voltage conversion circuit in parallel with the pair of measurement electrodes, respectively, and in a state where the calibration element and the pair of measurement electrodes are switchable,
• a voltage signal output from the voltage applying circuit and having the specific frequency has a sine wave obtained by tuning a voltage signal of a square wave with a low pass filter having a quality factor value which is from 1.5 to 3, the two or more calibration elements are elements having different phases, respectively, and
• the characteristics measurement means calculates a calibration matrix Q of the current-voltage conversion circuit from two or more calibrating detection values measured by using the two or more calibration elements, respectively, and true values to be originally obtained by the two or more calibration elements, to calibrate a measurement detection value measured between the pair of measurement electrodes, by use of the calculated calibration matrix Q.