To facilitate the grouping of icons and to construct a space for the grouping with a desired width by adjusting the interval of the icons at a position instructed on a display screen.

An area 3a storing document data is an area for reading document data from an external storate device 7. At the time of the editing operation of a document, the inside of the area 3a storing document data on RAM 3. An area 3b storing a customize information stores information concerning a presently constructing tool bar. In the area 3b, function numbers corresponding to the icons of each by one to one, the number of spaces expressing the number of dividing spaces accompanying the icon are arranged according to an order from the head by the number of th icons on a constructed tool bar. An additional space is optionally set such as providing a single space with a width quarter as large as the width of the icon or a specified number of dots.