PURPOSE: To obtain the data having a small error and the high accuracy by sticking a drawing or a command menu within a reading range of a digitizer and turning the hit drawing or menu into the image date to show this date on a display.

CONSTITUTION: An image input device 3 is provided together with a host computer which processes the image data inputted from the device 3, and a digitizer 2 which contains 8 display device 7 that is used as a pointing device of the computer 1 and shows the data in the reading range of the image data. Then the computer 1 is connected to the digitizer 2 via a serial circuit, and the image data is inputted by the device 3 and transferred to the computer 1. The computer 1 performs the vector/raster conversion processing of the image data and shows this processed data on the device 7 in the reading range of the digitizer 2.