The present invention relates to a steel reef which is one of artificial reefs sunk and installed on sea-bed, and more specifically, to a steel reef having four pod frames constituting a tetrapod, wherein the pod frame comprises angle frames to have the shape of one leg, while a block case into which a refillable vegetation block can be inserted is partitioned inside a central portion of respective pod frames. A main reef unit having a tetrapod shape is manufactured by integrally connecting rear-end parts of the respective pod frames while front-end parts of the respective pod frames are connected by a reinforcement frame. Thus, three pod frames are seated on sea-bed, and the main reef unit can be easily manufactured by an engineering method by which the sectional surface of a central point of the respective pod frames is joined while having a stable structure very robust to turnover. Installation is easy due to the lightweight in comparison with a concrete reef or tetrapod of the same size, and maximization of a reef function can be planned due to enough securement of a common area in comparison with a large tower type steel reef. Swarm of various kinds of fish from stereotactic lower layer fish to migratory upper layer fish can be formed, and formation of a spawning ground of various kinds of fish and a hiding space for fries are easily ensured based on a vegetation block. In particular, installed around a cylindrical steel pipe pile of a marine wind power generator which is buried by drilling a bedrock area of seabed, the tetrapod reef can be used for a purpose of a protective structure such as prevention of scours.본 발명은 해저면에 침설되는 인공어초 중 강제어초에 관한 것으로서, 더욱 상세하게는 테트라포드를 이루는 하나의 다리 형상을 가지도록 앵글프레임을 이용하여 총 4개의 포드프레임을 제작하는 한편, 각각의 포드프레임 중앙측 내부에 식생블록의 충진식 삽입이 가능한 블록케이스를 구획하고, 상기 각각의 포드프레임 후단부를 일체로 연결하여 테트라포드 형상의 어초본체를 제작하되, 각각의 포드프레임 선단부측이 보강프레임에 의하여 연결되도록 함으로서, 3개의 포드프레임이 해저면으로 안착되어 전도에 매우 강한 안정적인 구조를 가지면서도 각각의 포드프레임 중심점 단면을 접합하는 공법으로 손쉽게 제작이 가능하고, 동일 크기의 콘크리트 어초나 테트라포
