The utility model discloses an alarm type safety helmet, including shell body, interior casing, photoelectricity alarm lamp, sound generating mechanism, controller, battery, speedtransmitter, electromagnetic shaker, battery, be provided with the line of induction in the cavity between shell body and the interior casing, the line of induction is the half -circular arc of vertical setting, and each line of induction uses the vertical central line of safety helmet to distribute as the even circumference of axis, does not feed through each other between the line of induction, and connection director's voltage detecting port is distinguished at the both ends of line of induction, photoelectricity alarm lamp, sound generating mechanism, electromagnetic shaker are connected to the control port of controller, speedtransmitter's signal output part connection director's signal reception port, the electric current size is judged to the factor of magnetic field intensity, induction coil cutting magnetic induction line speed of synthesizing, the reliability of safety helmet has been improved, can respond to the current magnetic field of peripheral 180 degrees within ranges, through dangerous the direction of current flow of sound indiation and distance, possess the alarm mode of sound, light, vibrations simultaneously, improved the range of application of safety helmet.