A method and gas removing apparatus removes non-condensate gas from a heat pipe. The gas removing apparatus includes at least one heating unit, a sealing unit and a height-adjusting unit. The heating unit heats the heat pipe and includes a clip to clamp the heat pipe. The sealing unit is placed atop the heating unit and outside an opening of the heat pipe. The height-adjusting unit supports the heating unit and adjusts a height of the heating unit according to the length of the heat pipe, whereby the clip clamps on a lower portion of the heat pipe. During the removing operation of the non-condensate gas, the heating unit only heats a bottom portion of the heat pipe.