A key structure, including a keycap, a movable mechanism, a support plate, a circuit board, and an indicator light-emitting element. The support plate and the movable mechanism pivotally connected to the support plate are disposed above the circuit board. The circuit board has a groove, and the indicator light-emitting element is embedded in the groove and is aligned with the keycap. The indicator light-emitting element emits light upward. The light may be directly emitted into the movable mechanism and is subsequently emitted outward through a light hole of the keycap.