PURPOSE: To provide a heat insulation method for a piping which is formed of a hard heat insulating raw material to have high insulating property and to be strong against the external vibration.

CONSTITUTION: A tubular insulator 2 formed of a hard heat insulating raw material is ring-opened, and the ring-opened tubular insulator 2 is wound along the outer periphery of a pipe 1. Further, a tube 6 made of thermal contraction raw material is laid on the outer periphery of the tubular insulator 2, and the tube 6 is contracted by heating to fix the tubular insulator 2 to the outer periphery of the piping 1.