Disclosed is an apparatus for realizing an alarm function using a mobile terminal and a charging device for charging the mobile terminal. The mobile terminal includes a controller for generating an alarm control signal a predetermined time period ahead of a predetermined alarm time, and a first interface for transmitting the alarm control signal to the charging device. The charging device includes a second interface for receiving the alarm control signal from the mobile terminal, and a lamp driver for generating a lamp driving signal for controlling a lamp in response to the received alarm control signal.