Disclosed is an alarm system on the marine structure against the vessel collision such as a buoy or light buoy capable of ascertaining damage ofdamage to the marine structure and reliably clarifying where responsibility of a collided vessel lies by rapidly informing a remote site of a collision of the marine structure with the vessel when the marine structure collides with the marine vessel. An information acquisition unit collects and outputs collision information when a marine structure having a buoy or light buoy is damaged from collision with a marine vessel. A wireless data logger receives and transmitting transmits the collision information from the information acquisition unit through wireless communication. A remote server analyzes and compares the collision information from the wireless data logger with set information, and informing informs a manager of the occurrence of an impact applied to the marine structure using an alarm output means when the impact exceeds a predetermined magnitude.