The Inventing Room is Willy Wonka's favorite and most secret room. It holds all of his newest inventions and candy that still needs testing, examples being the Everlasting Gobstoppers, Hair toffee, and the Three Course Dinner Chewing Gum.
The room is a gigantic laboratory filled with machines that create candy, most notably the gum machine. Above the room, a giant catwalk allows the Oompa-Loompas to traverse atop the machines, accessing the controls of many machines and the room as a whole.
The Inventing Room plays a major role in Violet Beauregarde's downfall, as this is where she falls victim to the Three course Dinner Chewing Gum, turning into a blueberry.