The invention relates to an internally magnetic flywheel which comprises a plurality of magnets, an axle and a metal flywheel body. The metal flywheel body comprises a base plate, an annular portion and a plurality of blades, the annular portion is arranged on the base plate, an accommodating space is formed by the annular portion and the base plate, the magnets and the axle are arranged in the accommodating space, damping effects can be realized by the magnets and the metal flywheel body, and the axle is used for driving the metal flywheel body to rotate. The multiple blades are arranged on the base plate and are positioned on the periphery of the annular portion, and a first airflow channel is formed between each two corresponding blades.