It comprises the device body injecting oxygen in the water tub and is built in one side of the water tub according to the invention as to the oxygen solution apparatus for the water tub in which the dissolved oxygen rate is enhanced to up and down perpendicular and is installed; the inlet tube which is connected to the upper end portion of the device body and guided so that the inhaled water is flowed in into the water tub into the inside of the device body; the suction pump which is equipped in the inlet tube and in which water is inhaled in the water tub and which is flowed in into the inside of the device body; and the water which ***s through the guideline pipe it is equipped inside the guideline pipe, equipped in the form of the person and guideline pipe and discharge tube in the form of the spiral shape one side is connected in the inner center of the air supply part: discharge tube: device body which it guides the water in which oxygen is dissolved within the device body is again provided to the water tub it is equipped in the other side of the device body in the discharge tube 'ㄱ' it is supplied with oxygen to the inside of the device body it is connected to one side of the device body and the helix agitation blade in which the melting of oxygen is activated with the mixing of oxygen to the water. Therefore, while while oxygen is agitated with water the contact area and time are increased and water is small pieces broken with delicately the melting of oxygen is activated to the water and the dissolved oxygen rate of the water tub is enhanced and it is conveniently manufactured to the structure relatively of being simple and the oxygen solution apparatus for the water tub in which the manufacturing cost is saved can be provided.