Middle-stage phyllosoma of Panulirus japonicus (mean body length 11.5 mm) were cultured using 40-litre elliptical tanks with concave bottoms (85 cm long × 60 cm wide × 15 cm deep) in a flow-through system (24-25°C). The phyllosoma were fed with Artemia and mussel gonad. Survival rates to the puerulus stage were 54 ± 1%, 51 ± 0%, and 37 ± 9% at densities of 40, 60, and 90 phyllosoma/tank, respectively. The densities did not significantly affect the growth of phyllosoma. Major causes of phyllosoma mortality included moulting complications, bacterial disease, and cannibalism. The survival rates were significantly higher than in our previous studies, indicating that the new elliptical tank design may be suitable for mass culturing of phyllosoma. The survival of puerulus to the first juvenile stage was 83 ± 7% and did not differ between densities during phyllosoma rearing.