Studies　on　hydrogen　leakage　mainly　have　focused　on　the　influences　of　the　leakage　locations　and　geometrical　configurations　on　the　distribution　of　hydrogen　in　various　spaces.　In　this　study,　a　simplified　model　was　developed　to　examine　the　diffusion　of　the　hydrogen　leaked　into　a　small　fuel　cell　bus　with　seats.　The　impact　of　leakage　positions　and　leak　flow　rate　on　the　dispersion　of　hydrogen　in　a　cuboid　ventilation　space　(with　dimensions　L　x　W　x　H　=　5　m　x　2　m　x　2　m)　was　investigated,　and　concentrations　of　hydrogen　in　the　vicinity　of　the　corner　at　the　ceiling　were　of　particular　interest.　It　was　shown　the　peak　average　concentration　at　the　ceiling　increased　with　increasing　the　leak　flow　rate.　However,　the　duration　from　the　appearance　to　the　disappearance　of　the　combustible　hydrogen-air　mixture　decreased　with　the　increase　of　the　leak　flow　rate.　This　study　highlights　the　importance　of　leakage　positions　and　demonstrates　that　the　dispersion　of　hydrogen　is　faster　for　leakage　in　the　horizontal　direction.　The　proposed　approach　is　useful　for　improving　the　design　of　the　arrangement　of　hydrogen　storage　tanks　to　eliminate　consequent　accidents　or　minimize　the　harmful　impacts　during　an　accident.