Provided are a system and method of providing a voice-message call service. A mobile device (1000) that performs a call with an external mobile device (2000) comprises a control unit (1300) configured to obtain text, the text converted from voice data that is exchanged between the mobile device and the external mobile device, during the call between the mobile device and the external mobile device, and obtain input text input to the mobile device and provided text that is received from the external mobile device; and a display unit (1210) configured to arrange the text, the input text, and the provided text and display the arranged text, input text, and provided text on a screen of the device, during the call between the mobile device and the external mobile device.