To strengthen the Achilles's tendon as well as leg muscle by composing a sandal with a material higher on the front and lower on the rear as a base so that the user's foot is kept in such a position when he wears it.

An in-sole 1 of the sandal is made of skin or resin having appropriate elasticity. A material 3 has a heel 3e of specified height, a toe 3f higher than the heel 3e and a middle sole 3a placed between them on the bottom having approximately identical shape with the in-sole 1 to touch flat the ground. An outer sole 2 having an identical shape with the bottom surface 3a of the material 3 is made of skin or resin and glued to it by an adhesive agent. Further, a strap 4 as well as a belt 5 to hold fix the foot are applied onto the in-sole 1.