Abstract: A free-size hat is capable of fitting wearers having a range of head sizes. The free-size cap including both cap and hat regardless of the fabric can provide a free-size function by accommodating various head sizes of the wearers with slits being formed on the crown and the brim. The structure of the present invention permits either a hat or a cap to be designed which is produced easily, attractive in use or other time by keeping shape, comfortable for the wearer by causing no oppression, and further provides the advantageous feature of multiple size capability.