FUEL FOR USE IN FUEL CELL

A fuel for a fuel cell system comprising 0.5-40 mass % of oxygenates in terms of an oxygen content based on the whole fuel. The fuel for a fuel cell system has a high power generation quantity per weight, a high power generation quantity per COemission, a low fuel consumption, a small evaporative gas (evapo-emission), small deterioration of a fuel cell system comprising such as a reforming catalyst, an aqueous gas shift reaction catalyst, a carbon monoxide removal catalyst, fuel cell stacks and the like to maintain the initial performances for a long duration, good handling properties in view of storage stability and inflammability and a low preheating heat quantity.