PURPOSE:To facilitate installations of a fuel cell, a storage battery and a peripheral unit of an electric road vehicle using the fuel cell and inspection and maintenance operations. CONSTITUTION:A space of a perpendicular direction to a traveling direction of an electric road vehicle is provided at an interval position of front wheels and rear wheels vehicle body. A power source 4 formed by unitizing a fuel cell 6 for generating a current by a chemical reaction of hydrogen with oxygen in the air, hydrogen storage means for supplying fuel hydrogen to the cell 6 and a storage battery 7 for storing power generated from the cell 6 is detachably stored in the space. The power source 4 is electrically connected to a vehicle drive motor 10 provided at the body side through a detachable connector 9.