To provide a helmet that offers good ventilation while minimizing restrictions on appearance. [Solution] The helmet according to the present disclosure comprises a helmet shell, a first protective wall portion disposed inside the helmet shell and comprising a pair of front first walls that extend in a direction approaching the crown from the
forehead and are formed on either side of a first
virtual plane that includes the midline of the
human head, a pair of rear first walls that extend in a direction approaching the crown from the back of the head and are formed on either side of the first
virtual plane, and a first annular wall provided on the crown between the pair of front first walls and the pair of rear first walls, and an inner member comprising a right head protective wall portion provided on the right side of the head and a left head protective wall portion provided on the left side of the head.