NOVELTY - The hydrogen supply apparatus (10) has modification portion (46), heating portion (48), mixer (60), detector (90), and self-ignition suppression unit. Portion (46) produces fuel gas having hydrogen from supplied raw material. Mixer mixes combustible gas and support-combustion gas. Detector detects condition at which self-ignition of combustible gas tends to produce in mixer or heating portion. Self-ignition suppression unit operates, when detector outputs detection signal, such that self-ignition of combustible gas is optionally suppressed.    USE - For supplying hydrogen used as fuel for hydrogen consumption apparatus such as fuel cell of fuel cell system.    ADVANTAGE - The hydrogen supply apparatus efficiently suppresses self-ignition of combustible gas in heating portion, which heats modification portion.    DETAILED DESCRIPTION - The hydrogen supply apparatus (10) has a modification portion (46), a heating portion (48), a mixer (60), a detector (90), and self-ignition suppression unit. The modification portion performs modification process, which produces fuel gas containing hydrogen from supplied raw material. Combustible gas and support-combustion gas, which are supplied, are contacted with a catalyst, and catalyzed combustion is produced. The heating portion supplies heat produced in connection with the catalyzed combustion to the modification portion, as a heat for performing the modification reaction. The mixer mixes the combustible gas and support-combustion gas supplied by the heating portion. The detector detects the condition at which self-ignition of combustible gas tends to produce in the mixer or heating portion, and outputs a detection signal. The self-ignition suppression unit operates, when the detector outputs the detection signal, such that the self-ignition of combustible gas is optionally suppressed.    DESCRIPTION OF DRAWING(S) - The figure shows the outline whole structure of fuel cell system having the hydrogen supply apparatus. (Drawing includes non-English language text)    Hydrogen supply apparatus (10)    Fuel cell (14)    Modification portion (46)    Heating portion (48)    Mixer (60)    Detector (90)