In the top shell, Turbo (Batillus) cornutus, the effects of daily periodicity, hypoxia and water temperature on the respiratory parameters were examined by measuring amount of oxygen uptake, oxygen utilization at the gill, ventilation volume in gill and activity of cilium of the gill. The top shell showed diurnal rhythm in which the amount of oxygen uptake, the ventilation volume, the activity of cilium and the critical point of oxygen uptake under hypoxia (Pc) decreased in the daytime (13:00-15:00) and increased in the nighttime (20:00-21:00). Pc increased with the rise in the water temperature : oxygen saturation 27% at 13℃, 42% at 19℃ and 68% at 29℃. The ventilation volume and the oxygen utilization increased with the decrease of the oxygen saturation, but the activity of cilium decreased. Regardless of the acclimation temperature at 13-29℃, the amount of oxygen uptake, the oxygen utilization, the ventilation volume and the activity of cilium increased to 31℃ with increasing the water temperature.