We have been conducting a huge scale analysis for the full-wave electromagnetic field using the finiteelement method on various kinds of massively parallel supercomputers, such as K Computer and Fugaku in Japan. Through the whole simulation task including its pre- and post-processing, however, now the mesh generation step becomes the clear bottleneck. Currently, we are developing a fast and robust tetrahedral mesh generation technique based on the quad-tree/octree method. Detail of the mesh generation algorithm will be explained and some examples of huge scale mesh generation will be demonstrated in the presentation.