To provide a practicable and inexpensive crime prevention alarm notification system for a motorcycle having an effect as the theft prevention means for a motorcycle body.

This crime prevention alarm notification system comprises a generally commercialized and used chain type lock for the motorcycle, a loop-shaped circuit wiring wound on a chain, an alarm notification part having a cut detection circuit capable of detecting the breakage of the chain even when any part of the chain is cut, a crime prevention buzzer generating alarm sound, a battery, a transmitter, and a transmission antenna, and an alarm receiving part with a vibrator or a buzzer and a battery which determines the receiving antenna receiving radio transmitted from the transmitter, the receiver, and codes and, when the results of the determination match the expected ones, notify the results. This system can be post-fitted to a commercial chain type lock or wire lock without being affected by the locking structure of the lock.