To provide a nonslip and safe sandal which is worn when a person with a diseased foot utilizes a pool for a rehabilitation exercise, and which does not impose burden on the foot because of fitness and lightness.

The sandal includes: a vamp part 3; instep parts 4; a heel part 5; and an insole 2. The vamp part 3 is continuously arranged from the front end 6 of the insole 2, and returned upward and backward at a return part 7 so as to cover an instep. A sandal thong is formed by the return part 7, and lock parts 11 to be engaged with the instep parts 4 are formed at both the ends of a recession 10 which is arranged in the center part 9 of a distal end 8 in the vamp part 3. The instep parts 4, and the heel part are successively erected in both the side parts and the rear part from the insole 2. A double-soled pocket 12 is arranged in the insole 2, and a sheet material 15 excellent in grip performance is disposed on the outer surface 14 on the sole.