PURPOSE: To manufacture a tube of superior heat shrinkability in the diameter direction by heat shrinking a tubular body composed of a thermoplastic elastomer composition containing a specified copolymer at the specified degree of crosslinking in the direction square to the length direction.

CONSTITUTION: A thermoplastic elastomer composition containing 30-70wt.% of an ethylene-propylene-dien copolymer and 70-30wt.% of an ethylene vinyl acetate copolymer (5-30wt.% vinyl acetate content) is extruded out of a tube extruder, and electron radiation is emitted by an electron radiation emitting device to prepare an electron radiation emission strong tubeshaped body. The tube-shaped body is stretched (expanded) in the direction perpendicular to the lengitudinal direction to manufacture a heat-shrinkable tube 10. In that case, crosslinking caused by irradiation of an electron beam is preferably formed in a manner that gel percentage is 70-95%, particularly 80-90wt.%. The tube 10 is thermally shrunk and loaded to make it adhere to a required place of a body 11 to be installed.