PURPOSE: To extend the fittable time and improve workability by a fitting material for a ski boot with a crystalline thermoplastic resin having the glass transition temperature, the melt viscosity, and the endothermic peak temperature at the time of a temperature rise of specific values or below and the exothermic peak temperature at the time of a temperature drop of a specific value or above and having the difference between the endothermic peak temperature and the exothermic peak temperature of a specific value or above.

CONSTITUTION: A fitting material 25 for a ski boot 13 is fitted in an outer shell 15. The fitting material 15 is formed with a crystalline thermoplastic resin having the glass transition temperature of -20°C or below, the melt viscosity of 4000P or below, the endothermic peak temperature at the time of a temperature rise of 100°C or below, the exothermic peak temperature at the time of a temperature drop of 25°C or above, and the difference between the endothermic peak temperature and the exothermic peak temperature of 20°C or above. It can be deformed when it is applied with the heat of hot water or a drier for several min, and the time from a deformable area to an undeformabel area is made a time sufficient to set the ski boot 13.