Imaging of hydrogen gas concentrations were demonstrated using arrayed sensors system in the cylindrical diffusion tank-shaped simulator. The field effect transistor type hydrogen sensors with platinum gate electrode were used. The sensitivity of the sensors was around -34.1 mV/dec. and the response time was 1.2 sec. in average. By applying a sensor drive circuit to each sensor, the diffusion processes of the hydrogen gas were successfully obtained in time domain and two different processes were demonstrated using 100% hydrogen gas. Theseresults indicate that real-time monitoring of the hydrogen gas distribution can be possible. Additionally, the calibration method of the acquired data was proposed. © 2009 IEEE.