Abstract: An automatic plug removing apparatus has a conveying section and a plug removing section and, while a plurality of containers having test samples therein and sealed with plugs are being conveyed on a batch basis, the plugs are automatically removed from the containers. The plug removing section includes a member for holding a plurality of containers in an immovable state, a member for grasping the plugs provided to the containers and then removing the plugs from the containers, the grasping member being rockable and vertically movable by driving members, and partition plates insertable into gaps between the containers to provide isolated spaces for respective containers and prevent contamination between samples. A suction block may be added to suck the air in the vicinity of upper openings of the containers to eliminate a mist of samples floating thereabout.