The uranium adsorption tests using model bed units reduced to a scale of 1/4 from the adsorbent system proposed in the 1st report and packed with the adsorbent of fiber bundle type were carried out towing in the velocity of about 2 knots for 30 hours and mooring for 37 days in Imari Bay. The pressure distribution around the unit was measured and flow distribution in the unit was calculated for the towing test. And the uraniun adsorption of the adsorbent enclosed in the unit was simulated numerically. A good agreement can be seen between the measured and simulated uranium adsorptions. For mooring test, it was proved that the ability of adsorption was not decreased even if the adsorbent was keeping in underwater bed unit covered with the net of shield light during 37 days. Furthermore, numerical simulation of this system was carried out for practical operation in the ocean and the production cost of uranium extraction was calculated to be about 55, 000 yen/kg-uranium for extraction period of 60 days.