A powder feeding apparatus of manufacturing a heat pipe includes a vibration tray having a supporting board and a plurality of pipes positioned in the supporting board of the tray. A mandrel is coaxially inserted in each of the pipes. A feeder is located corresponding to an end of each pipe for feeding powder into the pipe. A vibration source is located under the tray to drive the tray to vibrate with substantially a same amplitude in a vibration direction when feeding the powder into the pipes from the feeder.