PURPOSE: To re-use an auxiliary screen designed by means of using an electronic computer only by means of readjusting a part and to verify the effectiveness.

CONSTITUTION: A screen device 1 inputting layout definition information of a screen in the middle of design while it is displayed, a definition device 2 executing definition based on the input, a screen information storage device 3 storing screen information from the definition device 2, and a screen transition device 4 defining, storing and displaying the display order of screen information are provided. The definition device 2 consists of a basic screen definition device 2a defining a ruled line, a fixed heading, an item and a color, a screen size definition device 2b defining a size, a display start position definition device 2c defining a display start position and a background switch definition device 2d defining whether a previous display screen is to be deleted or it is to be remained. The screen transition device 4 consists of a screen transition definition device 4a deciding the display order of plural pieces of screen information, a screen transition storage part 4b storing the display order and a screen transition execution device 4c displaying data in accordance with the display order.