Radiological aerosol generated from radio-activated metal cutting is a significant risk factor that must be considered for radiological hazards on a worker. For minimizing the exposure of a worker, it is important to understand the distribution of particle size and mass. This study measured the aerodynamic distribution of aerosols generated from the plasma arc cutting on steel alloys by using an electric low pressure impactor. We compared the impact of plasma cutting conditions with various plasma arc current (75, 90, 125 A) and cutting length (3, 6, 15 cm) on the aerodynamic distribution of aerosols. We confirmed the higher plasma arc current, the more aerosol with a larger particle than 0.1 mu m was produced. The optimal current value of suppressing ultrafine dust generation was suggested through the analysis of kerf width and fine particle fraction by increasing plasma arc current. The study of plasma arc current influence on aerosol generation could be helped to potentially minimize worker's exposure by carefully selecting the cutting conditions.