The invention relates to a puncher for a steel plate. The puncher comprises cylinders, locating plates, a workbench, a cam, a connecting ball, a connecting rod, a telescopic pipe, a drill, a driving motor, an oil tank, an oil pump, an oil supply pipe, an oil return pipe, an oil collecting tank, a filter screen and an oil nozzle, wherein output shafts of the cylinders are fixedly connected with thelocating plates; the workbench is arranged in the middle position of the upper end face of a base; the cam is fixedly connected with the output end of the driving motor; the connecting ball is fixedly arranged on the upper end face of the connecting rod; and the lower end of the connecting rod is connected with the drill through the telescopic pipe. According to the puncher, the steel plate is punched through electric energy, the position of the drill does not need to adjusted, errors are decreased, cost is reduced, efficiency is improved, the oil nozzle is connected with the oil tank throughthe oil supply pipe, the filter screen is arranged on the upper side in the oil collecting tank, the oil pump is connected with the bottom end in the oil collecting tank through the oil return pipe,lubricating oil can be automatically sprayed onto the drill, labor force is reduced, redundant lubricating oil can be recycled, and waste of lubricating oil is reduced.