1. A mobile terminal comprising: a wireless communication unit configured to perform a group chat with a plurality of counterparts; a display configured to display multiple chat windows of the performed group chat, the multiple chat windows including an upper instant message chat window and a lower non-instant message chat window, the lower non-instant message chat window including a text message chat window, an email chat window, or a short range wireless communication chat window; and a processor configured to: before the group chat is terminated in response to an intentional withdrawal from the group chat, or before the wireless communication unit is terminated from a first communication network and is newly connected to a second communication network, receive via the first communication network a first message including chat contents transmitted by at least one of the plurality of counterparts in the group chat, and control the display to display the chat contents of the received first message in the upper instant message chat window only, determine whether the group chat is terminated in response to the intentional withdrawal from the group chat, or whether the wireless communication unit is terminated from the first communication network and is newly connected to the second communication network, when the wireless communication unit is terminated from the first communication network and is newly connected to the second communication network, control the display to display an inquiry message for disconnecting from the group chat, and when an input is received via the inquiry message to disconnect from the group chat, control the wireless communication unit to not transmit any chat contents of any messages, and after the wireless communication unit is terminated from the first communication network and is newly connected to the second communication network, and an input is received via the inquiry message to not disconnect from the group chat, receive via the second communication network an unrequested second message including chat contents transmitted by the at least one counterpart in the performed group chat and control the display to display the chat contents of the received second message in the lower non-instant message chat window only.