Abstract: A work helmet for effecting an intercommunication between workers as well as between a central control room and respective workers, especially used for informing each workers of guide information adequate for emergency escape when a disaster occurs is disclosed. To this end, the work helmet includes a light-receiving element for receiving a light signal modulated with the guide information, an earphone for reproducing audibly the guide information, a light emitting element for emitting an outgoing light signal modulated with a speech signal supplied from a microphone, and an oscillator for generating a carrier having a frequency specific to the helmet, on which carrier said speech signal is modulated, so that the outgoing light signal is always modulated by the carrier serving as a helmet identifying signal by means of which the central control room can recognize and identify the worker wearing the helmet.