There is provided an information storage apparatus capable of storing information on a parked vehicle acquired before and after detection of unusual conditions with lesser amount of power to be consumed. During halt of a vehicle, at least one of image information and sound information of the interior of the vehicle is acquired by an anti-theft device main body, and the acquired information is transmitted from the anti-theft device main body to a drive recorder at a transmission interval that varies between before and after detection of unusual vehicle conditions by the anti-theft device main body. A drive recorder main body allows a second RAM to store therein information received from an anti-theft device at a second transmission period and information received from the anti-theft device at a first transmission period.