[en] So far for quantitative measurement, Bayard Alpert gauges (BAG) have been widely used. However, the gas emission from hot cathode gauges at ultrahigh vacuum is large, and the reproducibility is poor, therefore, the practical use for the measurement of gas emission rate and the system of small exhaust rate is difficult. Cold cathode gauges are useful for the measurement of gas emission rate at ultrahigh vacuum as the gas emission from the gauges scarcely occurs. In the cold cathode inverse magnetron gauge (IMG) on the market, the maximum exhaust rate is about 0.1 L/s, and there is not gas emission or exhaust action in ultrahigh vacuum region. The remaining problems are the accuracy of pressure indication and the change in the course of time due to contamination and others. In this experiment, the sensitivity of the IMG on the market was calibrated with a spinning rotor gauge in low and medium vacuum region, and with an extractor gauge in high and ultrahigh vacuum region. Also the change of the sensitivity was measured in contaminating environment and nitrogen atmosphere. These are reported. (K.I.)