Formation mechanisms of several kinds of segregation (V segregation, Centerline segregation, negative segregation near center part of bloom section) on continuous casting of bloom are investigated by some examinations on formation behavior of each segregation and distribution of solute element on cross section of bloom and using some analyses. As the results of these examinations and analyses, these formation mechanisms are clarified as follows. V segregation is gradually formed by flow of interdendritic liquid caused by negative gradient of pressure resulted from shrinkage flow existing on center side of cross section of bloom. The shrinkage flow on solidification proceeding to crater end forms the centerline segregation and the negative segregation near center of cross section of bloom, to promote mass transfer of solute in mushy zone, in vertical direction to solidification interface toward to center of cross section.