To provide a portable crime prevention tool capable of easily and naturally carrying without any distinction of a child and adult and surely ringing a crime prevention buzzer when a carrying person is involved in a criminal matter.

The portable crime prevention tool 1 comprises a buzzer body 2 having a ringing section electrically making a buzzer sound built in and having a front surface and rear surface, a fitting band 4 capable of fitting the buzzer body 2 on an arm of a human body, and switch 3 arranged on the surface of the buzzer body 2 and transmitting an electric signal to the ringing section in order to make the ringing section ring by making the switch push around. The switch 3 has an area greater than 1/3 of the surface area of the surface of the buzzer body 2.