PURPOSE: To remove the water remaining in the tube after the drainage operation of the water in a pipeline or a heat transmitting tube without imparting an adverse effect to the tube itself by a method wherein a dried clean cloth (gauze for example) or a sponge body is utilized.

CONSTITUTION: A vessel 1, provided with a vessel wall arranged with a multitude of small holes, is attached to the end opening of a vacuum hose 4 connected to a vacuum pump while pushing boards 3, between which the water adsorbing material 2 such as the sponge body or the like, for example, is pinched, are arranged before and after the vessel 1. Water drops or the like, remaining in the heat transmitting tube 6, may be removed through the sponge body 2 contacting with the internal surface of the tube 6 by scanning the body 2 into the axial direction of the tube 6 while reducing the pressure. According to this method, problems, such as corrosion and damage due to the condensation of impurity upon evaporation or the like, may be eliminated and the water remaining in the tube may be removed.