The utility model discloses a wheel disk broaching device. The wheel disk broaching device comprises a broaching machine base, a clamp base, a main oil cylinder, a broaching clamp, a cutter box, a cutter and a controller. Due to the fact that the broaching machine base, the clamp base, the broaching clamp, the main oil cylinder, the cutter and the cutter box are combined to broach a wheel disk of a flue gas turbine, the clamp base, the main oil cylinder and an indexing mechanism and a positioning mechanism in the broaching clamp automatically operate alternately so that the broaching device can achieve automatic cutter feeding and retracting, automatic indexing and automatic positioning, the labor amount of workers is relieved, operating time is shortened, and broaching precision of mortise grooves in the wheel disk is improved through machining; besides, due to the structural design of a manual locking mechanism, when a workpiece is broached, an inclination plate, an indexing plate and the workpiece can be connected more firmly, deviation of the workpiece is reduced in the broaching process, and broaching precision is improved.