A key module includes a key, a light emitting component, and a drive circuit. The key is operable between on and off states. The light emitting component is disposed adjacent to the key, and is capable of providing indicating light for the key. The drive circuit is electrically connected to the key and the light emitting component. The drive circuit is triggered upon switching of the key from the off state to the on state to provide a drive signal for driving the light emitting component to provide the indicating light. The drive signal has an intensity that gradually decreases over time once the key switches from the on state to the off state such that the indicating light provided by the light emitting component has a luminance that gradually decreases over time.