Headwear

Headwear comprising:

• a crown of planar fabric panels sewn together in-plane;
• a brim;
• and
• a size adjuster of a strip of fabric, the size adjuster being on a lower portion of the crown, around an entirety of a circumference of the crown or a part of the circumference of the crown,
• wherein:
• the size adjuster includes, in a space defined by a casing formed by the strip of fabric, a shape-changeable component that, at heat of a predetermined temperature or higher, is configured to soften and extend in a circumferential direction of the crown by a length that is greater than a length by which the shape-changeable component extends at heat lower than the predetermined temperature, in response to a tensile force applied to the shape-changeable component in the circumferential direction of the crown;
• the fabric panels have a contour and a mesh formed by cutting fabric on a bias such that a direction of the contour and a direction of the mesh intersect at an acute angle;
• and
• the fabric panels are sewn together using elastic thread, the crown and the brim are sewn together using elastic thread, or the crown and the size adjuster are sewn together using elastic thread.