A helmet includes a cap body (2), a shield plate (5) pivotally mounted at left and right opposite ends on the cap body (2) for pivotal movement between a closed position for closing the front face of the cap body (2) and an opened position for opening the front face, and a visor (6) which is attached to the cap body (2), a tip end of the visor (6) projecting forwardly at a position above the opening in the front face, thereby defining a housing chamber (C) between the visor (6) and the cap body (2) for receiving the shield plate (5) when the plate is pivotally moved to the opened position.