PURPOSE: To attain the effective use of the coordinate space of each type of input device by transmitting the coordinate data supplied from a coordinate input device directly to a host computer and therefore avoiding the deterioration of the compression factor of the coordinate space and the resolution of the coordinates.

CONSTITUTION: A microprocessor 2 decides whether the command given from a computer indicates a direct input mode or not. The input mode is set at l and 0 when the direct input mode is decided and not respectively. Then the input mode is stored in a work memory 3. The processor 2 processes data according to the processing routine of the coordinate data produced from a device and decides whether the input mode is equal to a direct input mode or not. If 1 showing a direct input, the coordinate data given from a tablet interface 7 or a keyboard interface 8 is defined directly as the coordinate value. Then the necessity for transmission of data is decided regardless of the input mode. If the necessity for transmission of data is decided, the coordinate data is sent to the host computer via a communication interface 5.