Abstract: The object of the present invention is to provide a method for manufacturing hydrogen-added water containing a large amount of microscopic bubbles and manufacturing equipment for the same so as to expand the industrial applicability of hydrogen-added water by injecting a large amount of microscopic bubbles. More specifically, a plurality of tubular structures, in which the diffusion chamber (5), having double tubes, is provided, and a porous element (6) having predetermined pore diameters, in the diffusion chamber (5) is provided and are substantially linearly arranged in a longitudinal direction. The raw water and hydrogen are supplied with one of the tubular structures, so as to form the mixture of raw water and hydrogen by mixing supplied raw water and hydrogen in the diffusion chamber (5). The mixture is passed through the porous element (6) and diffused therein. The mixture fluid of raw water and hydrogen is then supplied to an adjacent tubular structure under high pressure.