PURPOSE: To facilitate the visual recognization of a large screen, many screens, the documents, etc., by providing a work station which can carry out the window display, the split window display, and the transmissive window display respectively for data with use of plural display device.

CONSTITUTION: Three CRT display devices 51-53 are provided to serve as the output means of a work station 1. Thus the station 1 has a mode to individually display the windows on the devices 51-53 respectively. The devices 51, 52 and 53 are used exclusively as a screen window, a drawing/document window, and a data arrangement window respectively. A large screen is divided and displayed on these devices 51-53. Furthermore each of devices 51-53 can perform the transmissive window display and therefore can simultaneously and visually recognize different screens and also can compare the present and past states of the equipments with each other.