PURPOSE: To obtain a helmet effective for improving the safety consciousness of a worker or a driver and decreasing labor accident by using a specific construction to inform a worker or driver of information on the working or driving environment in the form of voice.

CONSTITUTION: A helmet body 10 is provided with a detection means such as sensor 18, a microcomputer unit 20 as a memory means and an information processing means, a speech synthesizing means 22 and a sound-output means such as head-phone 16. The information on the working or driving environment such as temperature and humidity is detected by the detection means and the information is transmitted to the information processing means. The inputted information is processed by the processing means and the corresponding message information is read out from the memory means. The outputted message information is converted into voice by the speech synthesizing apparatus and the voice is transmitted to the worker or driver by the sound-output means.