Ventilation type helmet

The utility model discloses a ventilation type helmet. Including a housing, a circular vent hole is formed in the top end of the shell; a plurality of drop-shaped vent holes are uniformly distributedaround the circumference of the circular vent hole by taking the circular vent hole as the center; wherein the circular vent hole and the drop-shaped vent hole are stepped holes, the upper parts and the lower parts of the circular vent hole and the drop-shaped vent hole are the same in shape, the lower parts of the circular vent hole and the drop-shaped vent hole are formed by expanding the upperparts in equal proportion, and stepped surfaces are formed among the upper parts and the lower parts of the circular vent hole and the drop-shaped vent hole. The lower portions of the round vent holesand the drop-shaped vent holes are formed by expanding the upper portions in equal proportion, hot air generated on the top of the head of a user in the using process can be concentrated and then dissipated in time, the round