The utility model belongs to steel plate drilling equipment field especially relates to a special perforating device of shaped steel. Including being used for the mount of suit outside the I -steel, the mount sets up channel -section steel and the fixed plate of setting at the channel -section steel top in the I -steel both sides including the symmetry, the top of fixed plate is provided with theback shaft, be provided with the electric drill subassembly on the back shaft, the electric drill subassembly is including setting up driving motor and the brill knife tackle spare of setting at the fixed plate front end in the fixed plate rear end, bore and to be connected through drive mechanism between knife tackle spare and the driving motor. Compared with the prior art, the utility model discloses a special perforating device of shaped steel, utilizes the electric drill subassembly after but the mount cooperation of suit on the I -steel is changed, makes special perforating device of shaped steel need not the manual work and controls, can accomplish the work of punching, the utility model discloses simple structure, processing make things convenient for, also can change on traditionalelectric drill, are fit for using widely on a large scale.