The invention relates to an automatic oil charging device for a meter. The automatic oil charging device comprises an oil storage barrel, an air pressure output device, a flowmeter, a control valve and a plurality of oil delivery pipes. The air pressure output device communicates with an air inlet in the upper portion of the oil storage barrel. The flowmeter communicates with an oil outlet in the bottom of the oil storage barrel. The control valve communicates with the multiple oil delivery pipes and is arranged on the down stream of the flowmeter. The ends of the oil delivery pipes are provided with oil outlet ports correspondingly. The oil outlet ports are made from rubber materials and connected with the oil delivery pipes through threads. Each oil outlet port comprises an oil discharging port with the diameter being greater than the diameter of an oil delivery channel in the corresponding oil delivery pipe. A ball plug is arranged in each oil discharging port. By adoption of the automatic oil charging device for the meter, oil charging operation can be conducted on a plurality of meters at the same time, the oil charging speed is increased, and the oil charging efficiency is improved; and meanwhile, oil can be supplied quantitatively, so that it is guaranteed that the oil charging quantity is stable and precise. In addition, the stability and airtightness of connection between the oil delivery pipes and the corresponding meters can b enhanced, operation is easy, convenient and fast, and the operating efficiency is effectively improved.