To provide a helmet which improves a work environment by preventing a worker from feeling a pain due to heat and sweat generated from a head.

The helmet is characterized by including: an external body 10 having a contour and being a helmet body for protecting the head of a wearer from an impact from the outside; an inner body 20 which is formed into a belt shape for holding the circumference of the head of the wearer at the internal face of the outer body 10 so that the internal face of the outer body 10 and the head of the wearer may be separated from each other at a constant interval; a cushion material 40 which is constituted between the outer body 10 and the inter body 20; a plurality of damping zones 50 which make the head of the wearer and the cushion material 40 may have a constant gap between them at the wearing of the helmet; an air blowing fan 71 which is inserted into the cushion material 40, and discharges air from the inside; and an air flow outlet 80 formed at a position corresponding to the outer body 10 so as to supply outside air to the air blowing fan 71.