An apparatus for processing a call of a wireless LAN using a callback function and a method thereof are for connecting calls when target terminals (destination terminals) are converted into a keep-alive state from a keep-dead state (for example, out of an access point section or power is turned off) by periodically receiving state information of other terminals in a transmitting terminal. A structure is as follows: a terminal 1 or a terminal n periodically transmits a keep-alive signal to a wireless LAN exchange; the wireless LAN exchange considers a terminal from which the keep-alive signal is not transmitted as a keep-dead terminal, and transmits an the telephone number list of the keep-dead terminals to each terminal; after information between the terminals and the wireless LAN exchange is periodically transceived, when users substantially attempt calls to target terminals, a callback service is requested if telephone numbers of the target terminals are stored in the telephone number list, and the calls are automatically attempted to the target terminals from the terminal in case the target terminals are converted into a keep-alive state from a keep-dead state.