To provide a blower unit for helmet, which can be easily attached to a helmet since it is composed of a flexible material, and further can provide a safe and comfortable cool feeling by generating a spiral convection of externally intake air on the inside of the helmet and pushing the air including heat and moisture within the helmet to the outside.

A blower unit includes: a pair of palm-sized air pumps 13 to be attached to both sides of a helmet 12, each of the air pumps having an intake port 15 and an exhaust port 16; and a pair of blowing tubes 14 connected to the exhaust ports 16 of the pair of air pumps 13 respectively, and extended to the inside of the helmet 12. Each blowing tube 14 includes an air jetting port 20, and a flow of air is generated inside the helmet 12 by the air blown out through the air jetting port 20 to discharge the air inside the helmet 12.