The present invention relates to an oxygen dissolution apparatus and an aquafarm having the same. The oxygen dissolution apparatus rapidly produces high quality oxygen water with a high degree of saturation of dissolved oxygen by making ultra-finely granulized water and oxygen gas come in contact with each other in an effective manner. Accordingly, the oxygen dissolution apparatus can maximize duration of dissolving time and thus prevents death of fish and shellfish caused by lack of dissolved oxygen and also prevents stress having negative influence on growth of fish and shellfish even in a situation of sudden increase of the number of fish and shellfish in an aquafarm. The oxygen dissolution apparatus comprises an oxygen dissolving member which is installed in the middle of a circulation pipe, is connected to an oxygen tank, and dissolves oxygen in circulated water. The oxygen dissolving member comprises: a phase transformation module comprising a spraying head, which transforms water in a liquid phase, transferred through the circulation pipe, into a mist phase water in an ultra-fine phase and sprays the mist phase water, and a radial flow fan which discharges mist phase water, which is sprayed by the spraying head and has a low speed, at a higher speed； and a communication pipe which receives supply of mist phase water, discharged from the phase transformation module, as a front end portion communicates with the phase transformation module, and, at the same time, receives supply of oxygen, as the communication pipe is connected to the oxygen tank, and enables the transferred mist phase water in an ultra-fine particle phase and the oxygen in a gas phase to come in contact with each other at an increased speed in a narrowed flow channel as a protrusion, which gradually reduces an inner diameter and increases the inner diameter to an original condition and forms a narrow flow channel in a middle point, is arranged therein.본 발명은 양식장용 산소 용존장치 및 이를 구비한 양식장에 관한 것으로, 초미
