A multi-window communication system performs a communication and telewriting between terminals having multi-window functions. This system inputs commands for a window frame change, a screen scrolling and various function execution designation, and analyzes and executes a command inputted by said inputting means and transmitted from another terminal. It displays window display data stored in a memory under the control of a command analysis, and transmits and receives transmitting and receiving signals to or from another terminal, under the control of a command analysis. Then, the system maintains window management data, changes a window frame and controls a scrolling of a window screen, under the control of the command analysis.