The present invention relates to a lower frame for cage culture capable of preventing corrosion caused by seawater and optionally adjusting the interval between inner frames and to a manufacturing method of the lower frame for cage culture. A conventional lower frame has the problems of being corroded by seawater and not easily assembled. The present invention shows a lower frame for cage culture comprising an elbow pipe and a T-shaped pipe which are made of a synthetic resin. In regard to the lower frame for cage culture, the elbow pipe has a pair of connecting parts having a space formed inside. In addition, a pair of penetrating parts communicating to each other are formed on both sides of the T-shaped pipe, and a connecting part having a space formed inside is formed in front of the T-shaped pipe. The end of a coated pipe where a coating layer (32) made of a synthetic resin is formed outside is inserted into the connecting parts, and the coated pipe and the connecting parts are coupled by thermal bonding. Therefore, the present invention has effects of preventing corrosion caused by seawater as the coating layer is formed on the outside of the coated pipe and blocking the inflow of seawater by firmly coupling the end of the coated pipe to the connecting part of the T-shaped pipe and the connecting parts of the elbow pipe by thermal bonding, thereby preventing corrosion. In addition, a plurality of T-shaped pipes are formed to be moved in the longitudinal direction of the coated pipe, thereby allowing the interval between inner frames to be optionally adjusted in response to the lower frame manufactured into various sizes.COPYRIGHT KIPO 2015본 발명은 바닷물에 의한 부식을 방지할 있으며, 내측 프레임의 간격을 임의로 조절할 수 있는 가두리 양식용 하부틀 및 그의 제조방법에 관한 것이다.종래의 하부틀은 바닷물에 의해 부식되고 조립이 용이하지 않다는 문제점이 있는데, 이를 해결하기 위하여 본 발명은 합성수지로 이루어진 엘보와 티보를 포함하여 구성된 가두리 양식용 하부틀에 있어서, 상기 엘보에는 내측에 공간이 형성된 한 쌍의 연결부가 형성되며, 상기 티보의 양측에는 서로 연통되는 한 쌍의 관통부가 형성되고, 티보의 전면에는 내측에 공간이 형성된 연결부가 형성되며, 상기 연결부에는 외측에 합성수지로 이루어진 코팅층(32)이
