An apparatus for manufacturing hydrogen-dissolved water and comparison of hydrogen-dissolved water with tap water from a viewpoint of their bubble particle distributions detected with an aerosol particle counter. Figure 2-a: The rate of volume of indicated-size-bubbles versus the total bubble volume in tap water (dealing with the dechlorination) was analyzed by an aerosol particle counter (Beckmann-Coulter, Delsa Nano S). 2-a-1 and a-2: Micro-bubble particles with diameters over 3 μm in tap water had been occupied more than 50% in the histogram. In addition, five water property parameters of tap water sample were detected as follows. DH: 0.025 ppm, DO: 8.6 ppm, ORP: +250 mV, pH: 7.30, chlorine ion concentrations: 0.015 ppm. 2-b: The bubble-particle distributions in hydrogen-dissolved water were analyzed by an aerosol particle counter (Beckmann-Coulter, Delsa Nano S). 2-b-1: Nano-bubbling particles from hydrogen-dissolved water were abundant, and in contrast, the micro-bubble particles over 3 μm were scarce. 2-b-2: The nano-bubble particles with diameter under 1 μm have a higher occupancy than one of the micro-bubble particles. 2-c: A schematic view of an apparatus (Proposal No. 2005–177724, Japan Patent) for manufacturing hydrogen-dissolved water. The mechanism means that the minimum volumes of nano size droplets are produced to maximize their surface areas, and so a high-pressure hydrogen gas was strongly incorporated into droplets inside. Apropos, the tank includes a jetting nozzle, and a guide tube of hydrogen gas which was made from the conventional device. The main accessary parts and their indices are as follows: 1. Exhaust gas section, 0.01 Mpa; 2. Water supply section, 0.3 Mpa, 1 Batch = 15 L/8 min; 3. Hydrogen gas supply section, 0.9 Mpa, 0.55 L/min; 4. Outlet section of hydrogen-dissolved water; 5. Minute particles of silica quartz porphyry; 6. Microporous-filter hydrogen-jetting nozzle, where the pore diameter is 6.1 μm.