Connecting device for assembly type factory building

The connecting device comprises a middle column and an H-shaped steel beam, a steel beam connecting piece is installed on the middle column in a sleeved mode, steel beam installation openings are formed in the periphery of the steel beam connecting piece, protruding butt joint ends are arranged on the inner walls of the two sides of the steel beam installation openings, a bearing structure is arranged on the middle column, and the H-shaped steel beam is arranged on the bearing structure. The size of a square through hole, used for inserting connection, of the steel beam connecting piece is smaller than that of the bearing structure, the periphery of the steel beam connecting piece is of a trapezoidal structure protruding outwards, and the bottom of the steel beam connecting piece is borne by the steel beam connecting piece through the arranged bearing step; the situation that the weights of the steel beam connecting piece, the H-shaped steel beam and the ceiling support installed on the H-shaped steel beam ar