The invention relates to the technical field of teaching appliances, in particular to a hand guard blackboard eraser used for teaching. The hand guard blackboard eraser comprises a blackboard eraser body. The blackboard eraser body is provided with brush bristles. The hand guard blackboard eraser further comprises a handle, and the handle comprises a handheld end and a sliding end. The blackboarderaser body is provided with a blind hole, and the sliding end is located in the blind hole and is further provided with a sliding block matched with the blind hole. An elastic part is arranged between the sliding block and the blind hole. The handheld part is located outside the blind hole. An end cover is arranged at the opening position of the blind hole. The handheld end is provided with a hand guard sleeve, and a heating device is arranged inside the hand guard sleeve. The hand guard blackboard eraser used for teaching is simple in structure, capable of reducing use cost, easy to popularize and good in practicability. Writing on a blackboard can be erased cleanly and rapidly, time and labor are saved and the practicability is quite good. Due to arrangement of the heating device, the handle can be heated when the air temperature is low, hands cannot be frosted easily, and user experience is greatly improved.