An end effector configured to open and close a screw-type lid for closing an opening of a container body, is provided, which includes a container gripper configured to grip the container body, a lid gripper configured to grip the lid and be movable on a screw axis of the lid, a rotating part configured to rotate the lid gripper, a guiding part configured to guide the lid gripper being rotated by the rotating part to move on the screw axis, and a detector configured to detect that the lid gripper is moved to one of an opened position and a closed position of the lid. According to this, the end effector capable of appropriately opening and closing the screw-type lid while gripping the container body can be configured.