PURPOSE: To make an improvement of the adhesive strength, with a good fluidity provided when heated, as well as with a separation cleared when applied and a coming down prevented after being applied, by making the distribution proportion of grain size of inorganic filling agent to within a specific range.

CONSTITUTION: The distribution proportion of grain size of inorganic filling agent making a base cement 3 used for tubes is made to such ratio, as referenced from the U.S. standard, with a part not passing through 40 mesh screen being less than 3%, not through 10 mesh 25W40%, a part passing through 140 mesh being 49W65%, and through 200 mesh 10%. For instance, after a mixing made between a resin part of 10.02%, consisting of novolak phenol resin and natural resin with hardening agent included, and a calcium carbonate of 81.40% of the before said distribution proportion of grain size, a solvent (denatured alcohol) of 8.58% is added and kneaded to obtain the base cement 3.