To provide a technique for actualizing an apparatus for sending carbon dioxide into deep sea, and then dissolving and liquefying and storing the carbon dioxide at the deep sea, which apparatus is easily operated, at low pressure, is simply structured, safe, almost free from troubles, easily maintained and administrated and low- cost.

In the apparatus for dissolving and liquefying carbon monoxide and storing the carbon monoxide at the deep sea, a pipe for sending a gas-liquid mixed phase flow of carbon dioxide and sea water or the like under pressure is arranged from the surface of the sea water to the deep sea. Carbon dioxide and sea water are sent under pressure into the deep sea while generating the gas-liquid mixed phase flow of the carbon dioxide and the sea water by either of a method comprising operating both pumps for sending gas under pressure and for sending liquid under pressure or a method comprising operating only one pump for sending the gas together with the liquid under pressure. Thereby, the pressure of the gas-liquid mixed phase flow increases automatically, and the gas-liquid mixed phase flow is stirred, dissolved and liquefied during being sent under pressure according to the natural principle, and therefore, bubbles are cleared away and the ascending force is suppressed. Accordingly, carbon dioxide can be released into the deep sea at a small pressure sending force.