Phytoplankton of the Southern Ocean, 140-148$^{circ}$E and 40-53$^{circ}$S, was sampled from early austral summer Nov. 1995 to Dec. 1995 to examine cell abundance, cell volume and biomass (cell carbon) distribution across the fronts. A total of 90 phytoplankton taxa were identified. They were 50 diatoms, 37 dinoflagellates, 2 silicoflagellates, and 1 prymnesiophyte. 73 species were observed from north of the subtropical convergence zone and 71 species from south of the subtropical convergence zone. Pseudonitzschia spp. was the most widely distributed species. Nanoplankton predominated cell number of phytoplankton throughout the stations. The abundance of diatoms was higher than that of dinoflagellates. Total biomass profiles wre dependent to microphytoplankton biomass. Maximum cell number and biomass were observed from subsurface layer. Phytoplankton community changed across the subtropical convergence zone and 50-53$^{circ}$S (antarctic convergence zone), and physicochemical factors seem to controll the distribution.