A liquid filling apparatus has a vertical tube with bottom opening opened and closed by a valve. The tube is insertable into a container from above and supplies liquid to the container. A flexible separating disk extends radially from the bottom end of the tube. The tube with flexible separating disk is movable toward the container bottom and air in the container escapes between peripheral rim of the separating disk and container wall as the tube moves down until the flexible separating disk rests on the container bottom. The tube with flexible separating disk then is moved upwardly so that, between flexible separating disk and container bottom, an enlarging space is formed with upward movement. Liquid is supplied into this space through the open tube opening as upward movement continues. When a targeted liquid level is reached, the valve closes and the tube is pulled from the container.