The concentration and particle size distribution of non-metallic inclusions which suspended in the molten aluminum at 700℃ were measured by using LiMCA apparatus. The result revealed that the number of inclusions increased with increasing the applied current or decreasing the orifice diameter, while decreased with increasing the purity of aluminum. And also, it was found that the number of inclusions increased with increasing the amount of boron added to molten aluminum. This was found to be attributed to the formation of the inclusions of TiB and V₃B₂. It was investigated that the average concentration of inclusions in a constant volume of 20㎖ of molten aluminum was increased in the order of pure molten aluminum, molten aluminum containing 20ppm of boron and molten aluminum used repeatly in the experimental casting in this study.