To improve functional characteristics and comfortableness in wearing of ski boots by facilitating fine adjustment of the foot form size and shape in the boots in accordance with the foot size and shape of each user.

A soft inner boot 10 is provided to be installed inside an outer shell boot main body 1 of rigid synthetic resin. A foot form adjusting body 4 to absorb a gap (a) formed between the foot and the inner boot 10 is provided at parts of an inner circumferential side wall surface 1b inside the outer shell boot main body 1 to correspond to around a foot except for an instep surface part 11a, a sole surface part 11b, and a toe part 11c.