"If you open up the Maintenance Panel, you'll be able to view the restaurant through the security Cameras" '- Phone Guy describing The Monitor' 


The Monitor is what the player uses to check through the cameras to know the whereabouts of the Animatronics  within the Restaurant
Monitor Gif

The player also uses this to help survive, as the player will know the animatronics' locations, meaning that they aren't in the Office, but if they aren't seen on any cameras, the player will have to check the Doors.

If the player doesn't move or go into the Monitor for a certain amount of time, an animatronic will automatically jumpscare the player.

The Monitor also has a feature called Night Vision which is meant to brighten a room anywhere in the diner (except for the Kitchen), switching off the Night Vision will leave the screen pitch black, and will only be able to know if an animatronic is there if their iris is glowing in the darkness (such as Candy, Cindy, Penguin and Chester).