Abstract: The invention relates to a device for marking the inside of a hollow glass item having at least one plunger comprising at least one raised and/or hollow pattern and a support assembly for said at least one plunger that can be moved between a first position in which the plunger is outside the item, and a second position in which the plunger is inside the item, and having radial movement means for moving said at least one plunger in a passive position spaced away from the inner surface of the side wall of the item and an active position pressed against said inner surface to imprint said at least one raised and/or hollow pattern.