PURPOSE: To enable the easy detaching work of a shield from the main body side of the helmet.

CONSTITUTION: Base plates 9 are attached to the right and left outsides of a helmet main body 2, and a rotation arm 17 is vertically rotatably pivotally supported on each base plate 9. An elastic deformable cover plate 19 for covering the base plate 9 and the rotation art 17 from the outside is disposed. The lower projected part 33 of a shield 6 can be attached or detached to the rotation arm 17. When the shield 6 is downward rotated so as to close the opening 5, the base plate 9 contacts with the lower projected part 33 of the shield 6 to stop release of the fitting. When the shield 6 is upward rotated so as to open the opening 5, the cover plate 19 elastically contacts with the lower projected part 33 of the shield 6 to stop the release of the fitting.