A fluidic device unit structure including a plurality of fluidic devices that are connected via channels, comprising: a plurality of pure-water opening and closing valves; a plurality of chemical-solution opening and closing valves which correspond to the plurality of pure-water opening and closing valves, respectively; and a base member including a pure-water circulation supply line and a chemical-solution circulation supply line, the plurality of pure-water opening and closing valves and the plurality of chemical-solution opening and closing valves being integrated via the base member, the base member further including a plurality of pure-water branch pipes that connect the plurality of pure-water opening and closing valves, respectively, with the pure-water circulation supply line, a plurality of chemical-solution branch pipes that connect the plurality of chemical-solution opening and closing valves, respectively, with the chemical-solution circulation supply line, a plurality of chemical-solution branch pipe outlets that are connected, respectively, to the plurality of chemical-solution opening and closing valves, the fluidic device unit structure being characterized in that a plurality of inclined channels that connect the plurality of pure-water opening and closing valves, respectively, with the plurality of chemical-solution opening and closing valves, the inclined channels guide pure-water from the pure-water opening and closing valves, respectively, to the chemical-solution opening and closing valves,the plurality of inclined channels being inclined with respect to a bottom surface of the base member, first mounting surfaces on which the plurality of pure-water opening and closing valves are mounted, respectively, and second mounting surfaces on which the plurality of chemical-solution opening and closing valves are mounted, respectively, the second mounting surfaces being located lower than the first mounting surfaces with respect to the bottom surface of the base member, wherein the chemical-solution flows from the chemical-solution circulation supply line to the chemical-solution branch pipe outlets when the chemical-solution opening and closing valves are opened, respectively, and wherein the pure-water flows from the pure-water circulation supply line through the inclined channel and the chemical-solution opening and closing valves to the chemical-solution branch pipe outlets when the chemical-solution opening and closing valves are closed and the pure-water opening and closing valves are opened, respectively. a plurality of pure-water opening and closing valves; a plurality of chemical-solution opening and closing valves which correspond to the plurality of pure-water opening and closing valves, respectively; and a base member including a pure-water circulation supply line and a chemical-solution circulation supply line, the plurality of pure-water opening and closing valves and the plurality of chemical-solution opening and closing valves being integrated via the base member, the base member further including a plurality of pure-water branch pipes that connect the plurality of pure-water opening and closing valves, respectively, with the pure-water circulation supply line, a plurality of chemical-solution branch pipes that connect the plurality of chemical-solution opening and closing valves, respectively, with the chemical-solution circulation supply line, a plurality of chemical-solution branch pipe outlets that are connected, respectively, to the plurality of chemical-solution opening and closing valves, the fluidic device unit structure being characterized in that a plurality of inclined channels that connect the plurality of pure-water opening and closing valves, respectively, with the plurality of chemical-solution opening and closing valves, the inclined channels guide pure-water from the pure-water opening and closing valves, respectively, to the chemical-solution opening and closing valves,the plurality of inclined channels being inclined with respect to a bottom surface of the base member, first mounting surfaces on which the plurality of pure-water opening and closing valves are mounted, respectively, and second mounting surfaces on which the plurality of chemical-solution opening and closing valves are mounted, respectively, the second mounting surfaces being located lower than the first mounting surfaces with respect to the bottom surface of the base member, wherein the chemical-solution flows from the chemical-solution circulation supply line to the chemical-solution branch pipe outlets when the chemical-solution opening and closing valves are opened, respectively, and wherein the pure-water flows from the pure-water circulation supply line through the inclined channel and the chemical-solution opening and closing valves to the chemical-solution branch pipe outlets when the chemical-solution opening and closing valves are closed and the pure-water opening and closing valves are opened, respectively.