To enable the fitting of the mouth of a vessel without allowing a liquid phase to remain in a vessel and without receiving the resistance of a dipping tube and to decrease the defective rate of products by providing part of the tube with a bellows or spiral cylinder in order to allow the universal meandering of the tube.

The dipping tube 1 is partly provided with the cylinder of a meandering part 2 formed with the bellows or spirals in order to allow the universal meandering of the tube 1. This cylinder is made universal in size buffer and directions and, simultaneously, the overall length of the dipping tube 1 is made longer than the depth down to the bottom of the vessel, by which the front end 3 of the tube is brought into contact with the bottom 5 of the vessel at all times. The fitting of the mouth of the vessel 4 is made possible and the product defects are decreased without allowing the liquid phase to remain in the vessel 4 and without receiving the resistance of the dipping tube 1. Then, the productivity, such as stabilization of the quality and the simplification of inspection stages, is improved.