Unlike four-wheel fuel-cell vehicles, fuel-cell motorcycles have little semi-closure space corresponding to the engine compartment of four-wheel fuel-cell vehicles. Furthermore, motorcycles may fall while parked or running. We conducted hydrogen concentration measurement and ignition tests to evaluate the feasibility of detecting leaks when hydrogen gas leaked from a fuel-cell motorcycle, as well as the risk of ignition. We found that the installation of hydrogen leak detectors is effective because it is possible to detect minute hydrogen leaks by installing leak detectors at appropriate points on the fuel cell motorcycle, and risks can be reduced by interrupting the hydrogen leak immediately after detection.