To realize a window system which can be applied to an optional existent software.

This window system automatically generates a window displaying the inputting form of the executing condition of a software in order that a user may designate the executing condition of the software by an interactive form. Shape designating information designating the shape of the window displaying the inputting form of the software executing condition is registered in a storing device 3 in advance and when the user designates the executing software window processing system 2 retrieves the device 3 to read shape designating information designating the shape of the window suited to the executing software from the device 3, prepares the shape of the window designated by the shape designating information and displays the window whose shape is prepared on a display screen 1.