NOVELTY - A hydrogen generating apparatus has a heating portion (10), a hydrogen-permeable membrane (20), a hydrogen generation portion (30) having a modification catalyst, a hydrogen permeation portion (40), a sweep gas supply unit (50), a hydrogen supply portion (60), a flame-propagation prevention unit (70a) and self-ignition prevention unit (80). The unit (70a) has flow path below quenching distance of hydrogen-containing sweep gas of portion (20) and/or portion (60). The unit (80) carries out cooling of hydrogen-containing sweep gas of portion (20) and/or portion (60).    USE - Apparatus is used for generating hydrogen used for internal combustion engine and exhaust gas purification apparatus.    ADVANTAGE - The hydrogen generating apparatus has reduced size, and excellent initial hydrogen generation property.    DETAILED DESCRIPTION - A hydrogen generating apparatus has a heating portion (10), a hydrogen-permeable membrane (20), a hydrogen generation portion (30) having a modification catalyst, on one surface of membrane (20), a hydrogen permeation portion (40) on other surface of membrane (20), a sweep gas supply unit (50), a hydrogen supply portion (60) which is connected to portion (40), a flame-propagation prevention unit (70a) and self-ignition prevention unit (80). The unit (50) is connected to portion (40) and supplies sweep gas to portion (40). The unit (70a) has flow path below quenching distance of hydrogen-containing sweep gas of portion (20) and/or portion (60). The unit (80) carries out cooling of hydrogen-containing sweep gas of portion (20) and/or portion (60).    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of hydrogen generating apparatus. (Drawing includes non-English language text)    Heating portion (10)    Hydrogen-permeable membrane (20)    Hydrogen generation portion (30)    Hydrogen permeation portion (40)    Sweep gas supply unit (50)    Hydrogen supply portion (60)    Flame-propagation prevention unit (70a)    Self-ignition prevention unit (80)