The present invention aims to provide a medical rubber stopper that is excellent in chemical resistance and airtightness while having good productivity. The present invention relates to a medical rubber stopper including: a disk-shaped head portion with a flange region; and a cylindrical leg portion protruding from the lower surface of the head portion and having a smaller diameter than the head portion, the lower surface of the flange region and the leg portion being laminated with an inert film, the lower surface of the flange region and/or the outer periphery of the leg portion being provided with an annular groove through which the base rubber is exposed.