Known as an example of conventional hydrogen supply systems is one disclosed in Patent Literature 1. The hydrogen supply system of Patent Literature 1 comprises a tank for storing a hydride of a starting aromatic hydrocarbon, a reactor for producing hydrogen by a dehydrogenation reaction of the starting material supplied from the tank, a purification means for purifying the hydrogen produced by the reactor, and a burner for heating the reactor. An off-gas from the purification means is supplied to the burner and utilized as a fuel for the burner. Here, using a dehydrogenation catalyst in the reactor in coexistence with hydrogen has been known to improve durability of the dehydrogenation catalyst. For such improvement in durability, a method for performing a dehydrogenation reaction in a reactor in coexistence with hydrogen by using a hydrogen supply system as in Patent Literature 1 so as to supply the reactor with a part of high-purity hydrogen obtained by the purification means has been known.