A real-time soil compaction meter that refers to the air injection subsoiler, is developed.  The final goal is to predict standarized soil compaction that is converted from soil moisture content, working resistance and working speed.  This experiment confirmed performance of predicting the soil moisture content and of measuring the working resistance was conducted.  The equipments of the meter are a working resistance measurement device received from the soil and a spectroscope measuring a light reflection from the soil surface.  The spectroscope using band pass filter detects 9 light signal level and the range of wave lengths is 650 - 1550nm.  The working resistance measurement device is composed by one load cell and four strain gage, and it can detect horizontal and vertical load acting to the chisel at the same time.  As the experiment condition, the running speed was 0.3m/s, the depth of chisel was 10cm, all signal were sampled 1kHz by A/D converter and stored to a hard disk on a computer.  Before running the meter, penetration resistance were measured 4 times by a cone penetrometer at one point, and the observed value of one point was assumed to be a mean value.  The correlation coefficient between the horizontal load predicted by the soil compaction meter and the penetration resistance measured by the cone penetrometer was 0.66.  The soil moisture content was predicted using the spectrum reflected from soil surface by the PLS-method based on the moisture content oven dried during 24 hours, and its prediction root mean square error (rmsep) was 0.71%w.b..