A keyboard device includes plural keycaps and a membrane switch circuit member. The membrane switch circuit member is disposed under the plural keycaps. The membrane switch circuit member includes a wiring board and plural separate covering pads. The wiring board includes plural first trace patterns and plural second trace patterns corresponding to the plural keycaps. The plural second trace patterns are disposed on the wiring board and separated from the plural first trace patterns. There is a gap between each first trace pattern and the adjacent second trace pattern. The covering pads are disposed over the wiring board. The plural covering pads are aligned with the corresponding keycaps and cover the corresponding gaps. The covering pad has a triggering trace pattern over the corresponding gap.