An automatic system was developed for the measurement of radiation using a magnetically levitated electrode ionization chamber. The system was used to measure background and K-40 gamma ray dose rates. The background dose rate measurement demonstrated high sensitivity and reliability of the system, and a low-level 4 K gamma ray dose rate was successfully measured: For the case of a 30-minute measurement, the detection limit of the system is 13 nGy/h. This measurement system will be useful as an area monitor to measure space dose rates.