Abstract: In a foot inclination angle measuring method of the present application, the shape of a foot 10 is measured in three dimensions. And, based on three-dimensional data on the measured shape of the foot 10, a two-dimensional cross section 30 of the foot 10 orienting in a front-rear direction, which includes a cross section of a heel of the foot 10, is obtained. Then, a central line C1 of the two-dimensional cross section 30 in a right-left direction is obtained and the angle of inward/outward inclination of the foot 10 is obtained from the angle of inclination (a) of the central line C1.