PURPOSE: To achieve both rapidity and low cost of a screen copy by a method wherein a background color which is represented by a color other than a tube surface color is taken as the tube surface color when an image screen with CRT display of various kinds of information processors is copied.

CONSTITUTION: A screen copy instruction-receiving part 1 performs instruction receiving which specifies a copy screen recognizes the specified screen, and instructs its content to a screen display data part 2. The screen display data part 2, when the background of a screen which receives a screen instruction is not of a tube surface color, performs data conversion which converts it to the tube surface color, and writes into a frame buffer 3 as a display data. A screen copy data part 4 reads the data which converted the background color to the tube surface color from the frame buffer 3, converts it to a data for printing the screen to be printed with a printer. After end of printing, the screen display data part 2 writes the background color which wad used as the tube surface color into the frame buffer 3 as the original background color again.