Ocean sequestration of the captured CO₂ from fossil fuel burning is a possible option to mitigate the increase of CO₂ concentration in the atmosphere. Moving ship type of CO₂ ocean sequestration is treated in this study. That is, liquefied CO₂ is delivered by ship to the site and injected into ocean depths of 1, 000 to 2.500m with a suspended and towed pipe by a slowly moving ship. In addition to the horizontal movement of releasing point, use of the rising journey of CO₂ droplets till they disappear by dissolution is effective for the dilution of CO₂ in seawater. The distance between the released depth of CO₂ and the disappearing depth depends on the initial size of droplets, the dissolution rate and the rising velocity. The possibility of generating relatively large size of droplets from moving nozzle was investigated in the previous report. In this report, the terminal velocity of CO₂ droplet under the deep-sea circumstances is measured in a large high-pressure tank, considering the influence of the hydrate film on droplet and the possible deformation when its size is relatively large. And the rising and dissolving behavior of CO₂ droplet is calculated to estimate the rising journey of CO₂ droplets in the scenario of the moving ship type of CO₂ ocean sequestration.