An information processing apparatus having a resume function which can maintain the security even when a plurality of users commonly use the apparatus. A work state at a power-off time of the apparatus is preserved together with a work state name including a user's ID in a different area in a plurality of preservation areas for resume function on a main memory for each user. When a power source is again turned on, data in the preservation area corresponding to the user's ID is used to reproduce the work state of the user at the power-off time. The work preservation areas can be provided on a file server apparatus in a network not needing battery back-up. When the information processing apparatus is used, a work state at a power-off time can be independently preserved and reproduced for each user.