The present disclosure provides a package device. The package device includes a first integrated circuit chip, a second integrated circuit chip, a first input/output pin, and a first electrostatic discharge protection element. The first integrated circuit chip includes a first internal circuit and a first input/output pad disposed on the first integrated circuit chip and coupled to the first internal circuit. The second integrated circuit chip is stacked on the first integrated circuit chip. The second integrated circuit chip includes a second internal circuit and a second input/output pad disposed on the second integrated circuit chip and coupled to the second internal circuit. The first input/output pin is coupled to the first integrated circuit chip and the second integrated circuit chip. The first electrostatic discharge protection element is coupled between the first input/output pad and the first internal circuit.