PURPOSE: To incessantly feed clean air, warm air, or cold air to the head section of a worker so that the work can be performed healthily, safely, and comfortably in the environment with dust, a malodor, high temperature, or low temperature.

CONSTITUTION: An air injection port is provided at the upper section of a dustproof helmet covering the whole head section and opened at the neck section, and a device feeding clean air, warm air, or cold air to the injection port from a blower 8 or an air compressor through a hose is connected to the injection port. A cock 9 adjusting the quantity of the fed air and a decompressor decompressing the compressed air are installed as required, and a heater or a cooler is added to the device when warm air or cold air is required.