We provide a foot attachment that, simply by being worn on the feet, helps maintain core flexibility and stability, contributing to core training. [Solution] The foot attachment 1 of the present invention is provided with a projection 6 that protrudes inward in the area from the big
toe 10 to the little
toe 14 on the
toe side of the instep. The projection 6 is knitted in the part that comes into contact with the second joint 10a of the big toe 10, the
second toe 11, the third toe 12, the
fourth toe 13, and the third joints 11a, 12a, 13a, and 14a of the little toe 14, and protrudes toward the second joint 10a of the big toe 10, the
second toe 11, the third toe 12, the
fourth toe 13, and the third joints 11a, 12a, 13a, and 14a of the little toe 14.