The streak line patterns of several wide-paddle impellers developed in Japanese mixer companies were estimated by numerical analysis. As predicted by Inoue, it was difficult to expect the streak line patterns from the velocity vector. It was found that the streak line patterns in the laminar region were different from each other even in the same Reynolds number depending on the kinds of impellers. The numerical analysis was also able to clarify that the liquid height influenced on the streak line patterns of the large paddle impellers, which had been made clear in the experiment.