PURPOSE: To provide a peripheral equipment changing device capable of changing the structure of the peripheral device during the operation of a computer system.

CONSTITUTION: A peripheral equipment management list 5 manages the information of the peripheral equipment such as a magnetic disk 2 and a terminal 3 which are connected to a computer 1. A peripheral equipment management list check smeans 9 checks the list 5 in removing the required peripheral equipment during the operation of the computer system. An operating system use inhibiting means 10 sets the peripheral equipment not to use the operating system 4 when the peripheral equipment is not in use and the system 4 is judged to permit the removal as the result of the check by the means 9. A peripheral equipment management list deleting means 11 deletes the information on the peripheral equipment which is not available in the operating system 4 by the means 10 from the list 5.