Referring to FIG. 1, a known fan structure 10 mainly comprises a casing 11, a bearing 12, a shaft 13, a fan blade 14, a stator 15, a silicon steel sheet 16 and a magnet 17. The casing 11 has a shaft seat 11a, the bearing 12 has an outer ring 12a fixed on the shaft seat 11a and an inner ring 12b. The shaft 13 penetrates and is fixed at the inner ring 12b of the bearing 12 and the fan blade 14 is fixed at one end of the shaft 13. The stator 15 is disposed on the shaft seat 11a of the casing 11, the silicon steel sheet 16 and the magnet 17 are fixed on an inside wall 14a of the fan blade 14. When the fan structure 10 is actuated, the inner ring 12b of the bearing 12, the shaft 13, the fan blade 14, the silicon steel sheet 16 and the magnet 17 start to rotate simultaneously. The known fan structure 10 is no longer applied for miniaturized or thinned electronic products that have been made in recent years because which has a thick and heavy structure entirely.