A decoupling device including a lead frame, multiple capacitor units, a protective layer and a packaging element is provided. The lead frame includes a cathode terminal portion and at least two opposite anode terminal portions disposed at two ends of the cathode terminal portion. The two anode terminal portions are electrically connected with each other through a conductive line. The capacitor units are connected in parallel and disposed on the lead frame. Each capacitor unit has a cathode portion and an opposite anode portion. The cathode portion is electrically connected with the cathode terminal portion. The anode portion is electrically connected with the anode terminal portion. The protective layer wraps at least one of the anode portion and the cathode portion of the capacitor unit. The packaging element covers the lead frame, the capacitor units and the protective layer. The packaging element exposes a bottom surface of the lead frame.