The invention provides a device for taking out broken bolts from a connecting shaft of a plate-strip vertical rolling mill. The device is composed of a magnetic seat drill, a drill die plate and four bolt supports, the drill die plate is fixed to the lower end face of the connecting shaft of a speed reducer of the vertical rolling mill through connecting bolts, and drill bit guide holes corresponding to all bolts liable to breakage on the connecting shaft of the speed reducer of the vertical rolling mill are formed in the periphery of the drill die plate; and a base of the magnetic seat drill is attracted to the lower surface of the drill die plate, the four bolt supports are fixed to the lower surface of the drill die plate and evenly distributed around the base of the magnetic seat drill, and each bolt support is provided with a fine-turning bolt corresponding to the base of the magnetic seat drill. According to the device for taking out the broken bolts from the connecting shaft of the plate-strip vertical rolling mill, by means of the magnetic seat plate, a stable installation surface for the magnetic seat drill can be provided, and accurate positioning and guiding can be conducted on a drill bit of the magnetic seat drill. By means of the device, drilling operation for conveniently and rapidly taking out the broken bolts from the connecting shaft of the plate-strip vertical rolling mill can be achieved, the device inspection and repair efficiency is greatly improved, and the labor intensity of maintenance workers is reduced.