To provide an information processor capable of returning to a screen output state, in which external equipment was connected to the processor by a user, without having a manual change made by the user.

IDs for every external equipment are prepared and stored in a database. The external equipment IDs are thereby referred to and utilized for the control of the screen output state when various external equipment are connected to or cut off from a computer 1. When the external equipment is connected, which work space to be displayed on which display device can be automatically set based on related information stored in the database. The external equipment connected to the information processor, and the screen output state at that time, are associated and displayed on the display device, thus providing the information processor capable of returning to the screen output state in which the external equipment was connected by the user, without the manual change made by the user.