UNDER-CRANE SAFETY MONITORING SYSTEM

PURPOSE:To surely alarm existence of a dangerous zone even in an insufficient light volume condition in a large place in a transport space by disposing a laser scan device at such a position as to be capable of forming a conical colored laser beam film in the dangerous zone under a member, and controlling an inclination angle of the laser beam film following movement of the member. CONSTITUTION:A laser scan body 11 having a colored laser beam source is provided at a rotary body driven continuously, and laser scan means 5-7 to form a conical colored laser beam film 9 by drive of the laser scan body 11 are provided. It is disposed at a position to be capable of forming the laser beam film 9 in a dangerous zone 10 under a member 4 transferred by a boom 3 of a crane, and the laser scan means 5-7 are controlled by a control device to let an inclination angle of the laser beam film 9 follow the movement of the member 4. The colored laser beam film formed in the dangerous zone 10 which is moving every moment can thus be recognized visually, thereby advance prohibition can be announced securely.