In a system for hydrogenation of an aromatic compound, an excessive temperature rise in the hydrogenation reaction unit is prevented, and the amount of the dilution gas to be circulated is minimized. The hydrogenation system (1) comprises a hydrogenation reaction unit (2) for producing a hydrogenated aromatic compound by adding hydrogen to an aromatic compound via a hydrogenation reaction, a separation unit (3) for separating the hydrogenated aromatic compound from a product of the hydrogenation reaction unit, and a transportation unit (4) for circulating at least a part of a residual component remaining in the separation unit after separating the hydrogenated aromatic compound therefrom to the hydrogenation reaction unit. The hydrogen supplied to the hydrogenation reaction unit consists of diluted hydrogen (L2) diluted by a dilution compound having a higher molar specific heat than nitrogen, and the dilution compound includes a component circulated to the hydrogenation reaction unit as the residual component.