The present invention relates to a prefabricated box configured to be freely manufactured and used by a user in a required size, the upper portion of which is provided with an installation groove is formed along the longitudinal direction and arranged in a rectangular frame, a lower frame consisting of a corner member； An upper frame formed at an upper portion and a lower portion of the upper horizontal piles and corner members, wherein an installation groove is formed along a longitudinal direction and disposed in any one of ㅁ, c, ㅡ, a； A vertical pile provided with a vertically mounted body and an installation groove； And a side plate inserted and installed in the installation frame of the upper frame and the lower frame and the vertical pile, wherein the corner members of the upper frame and the lower frame are coupled to the coupling groove on a surface perpendicular to the lower horizontal pile and the lower horizontal pile. Any one of the projections is provided, the corner members are coupled to the neighboring engaging groove and the engaging projection by the projection-groove fitting, the corner members and the vertical pile is fitted by the projection-ball fitting of the fastening projection and the fastening hole Side plates can be realized as boxes that are inserted and installed in the mounting frame of the upper frame, the lower frame and the vertical pile and assembled into a rectangular parallelepiped shape, and can be assembled without the use of screws and the effect of manufacturing boxes of various widths and heights. Since it can be assembled and dismantled without a separate tool, it can be quickly assembled and used.본 발명은 사용자가 필요한 크기로 자유롭게 제작하여 사용할 수 있도록 구성된 조립식 상자에 관한 것이고, 상부에는 설치홈이 길이방향을 따라 형성되고 사각틀 모양으로 배치되는 하부 수평파일과, 코너부재로 구성된 하부프레임과； 상부와 하부에는 설치홈이 길이방향을 따라 형성되고 ㅁ,ㄷ,ㅡ,ㄱ 중에서 어느 하나의 모양으로 배치되는 상부 수평파일들과, 코너부재로 구성된 상부프레임과； 수직으로 세워지는 몸체와 설치홈이 구비된 수직파일과； 상부프레임과 하부프레임 및 수직파일의 설치홈에 삽입-설치되는 측면판；을 포함하여 구성되고, 상기 상부프레임과 하부프레임의 코너부재는 하부 수평파일과 하부 수평파일과
