can be generated although aluminum is illustrated to have the form of the tube 110 and the aluminum wire 130 having the anode current supplied thereto is illustrated to be disposed within the tube the present invention is not limited thereto for example aluminum can have a plate shape that is the cathode current may be applied to the aluminum plate and the anode current may be applied to the aluminum wire spaced apart from the aluminum plate at a predetermined distance for the anodic oxidization reaction an acid electrolyte is circulated within the aluminum tube 110 it is preferred that a sulfuric acid solution of low temperature be used as the acid electrolyte when the acid electrolyte is circulated as described above hydrogen is generated around the aluminum wire 130 to which the anode current has been supplied and oxygen is generated in the aluminum tube 110 to which the cathode current has been supplied oxygen reacts with the aluminum tube 110 and thus alumina that is oxidization aluminum is slowly accumulated on the inside wall of the aluminum tube the accumulated alumina is formed as an alumina membrane here as in the above described anodic oxidization principle the acid electrolyte finely dissolves the alumina membrane when the velocity of dissolution and the growth speed of the alumina membrane are balanced pores can be formed in the alumina membrane the pore can be a uniform pore having a diameter of 10 to 150 u03bcm through the above process that is the anodic oxidization principle a thick alumina membrane having the uniform pores formed therein is formed on the inside wall of the aluminum tube.