PURPOSE: To prevent foot ache and shoe sore by having a spacer made of a shape memory resin, having the spacer adjustable to the shape of the foot and installing the spacer inside a toe portion, a plantar arch portion, a heel portion, and an outer shell of a shoe.

CONSTITUTION: An inner boot 4 is taken out of a ski shoe 2. A spacer 1 is then warmed up to a temperature where the spacer 1 is softened by means of hot air of a drier, etc. After the spacer 1 has softened, the inner boot 4 is returned to the ski shoe 2 before it hardens in cooling down. The ski shoe 2 is then worn, so that the spacer 1 is deformed to conform to the shape of a foot. In this state, while the ski shoe 2 is worn, the spacer 1 is allowed to cool down, so that it hardens. Accordingly, the spacer 1 fills a gap between the foot and the ski shoe 2, and thus it hardens while a toe portion of the spacer 1 supports the portion from the toe to the back of a foot, a plantear arch portion supports the arch and the sides or the foot and a heel portion supports a portion from a heel to an ankle, conforming to the shape of the foot. A ski shoe 2 fitting to the foot is thus obtained.