A dehydrogenation fuel theft prevention system for preventing the theft of dehydrogenation organic fuel containing hydrogen is provided. The dehydrogenation fuel theft prevention system is for systems including a reformer for dehydrogenating organic fuel containing at least hydrogen and a dehydrogenation fuel recovery tank for storing dehydrogenation fuel produced when organic fuel is dehydrogenated in the reformer. The theft prevention system is provided with a means for mixing an odorant as a component with a pungent odor other than the fuel components or a agent for coagulating the fuel components. The odorant or the coagulating agent is mixed when fuel is manufactured, distributed, utilized, recovered, or stored or fuel is about to be stolen.