PURPOSE: To administer proper far infrared rays by irradiation, by forming a light reflecting layer and a far infrared ray irradiation layer to the inside surface of a cap body and constituting the light reflecting layer of a heat ray impervious metal.

CONSTITUTION: A cup body 1 composed of a cloth material is constituted by forming a light reflecting layer 2 to the inside surface thereof and further forming a far infrared ray irradiation layer 3 to the surface of said layer 2 and an extensible member 4 composed of an extensible material capable of controlling wearing of a cap is sewn on the proper part of the cap body 1 and an extensible band 5 is mounted to the outside end edge part of the cap body 1 in order to wear the cap in a closely contacted state. The light reflecting layer 2 is composed of a heat ray impervious metal material. The light reflecting layer 2 and the far infrared ray irradiation layer 3 are formed by a bonding, or coating means when they have a plate shape. The extensible member 4 is arranged by bonding or sewing a rubber thin plate or extensible cloth material.