Abstract: A fan device having simultaneously foldable blades includes a rotatable driving unit. A plurality of supporting frames extend outwardly from the driving unit, each supporting frame has a pivot mounted on one end thereof. A plurality of shells are respectively mounted on the supporting frames, each shell has a center hole defined therein. A plurality of blades are respectively disposed on the shells. Each blade has an assembling portion disposed thereon. Each assembling portion has a through hole defined therein. A plurality of coupling rods respectively positioned between every two adjacent shells. When the driving unit rotates, the shells synchronously rotate and driving the coupling rods to be moved for simultaneously driving the blades to retractably fold/unfold.