To provide a computer system which uses a remote computer as a radio mouse.

This control method of the computer system includes a remote controller 10 having a plurality of function selection buttons for outputting different radio signals by selection by a user and a system control part which controls system functions according to radio signals outputted from the remote controller 10 and includes a stage for preliminarily setting mouse control functions corresponding to kinds of the radio signals outputted from each function selection button 14 of the remote controller 10, a stage at which the radio signals are outputted from the remote controller 10, a stage for confirming whether or not the use mode of the remote controller 10 is a mouse mode for obtaining the mouse functions and a stage for providing the system control part with the inputted radio signals by switching them to mouse function control signals when the use mode of the remote controller 10 is the mouse mode.