REACTION VESSEL, REACTION SYSTEM AND REACTION METHOD

PROBLEM TO BE SOLVED: To provide a reaction vessel capable of both decreasing capacity of a flow passage and forming a multilayer flow.SOLUTION: The reaction vessel for mixing a first and second liquids is composed of: (1) first flow passages, which is a plurality of flow passages each having a constant width and separately formed by a constant width in a width direction, and having a first nozzle on one end side for introducing the first liquid into the flow passage and guiding the first liquid introduced from the first nozzle to the other end side; (2) a second flow passage, which is one or plurality of flow passages each having a constant width and formed between the first flow passages, and having a second nozzle on an outflow end side of the first flow passages for introducing a second liquid into the flow passage; (3) a funnel-like part for contracting a width of the multilayer flow in which a flow of the first liquid discharged from the first flow passage in a belt shape and a flow of the second liquid discharged from the second flow passage in a belt shape are alternately arranged, along the flow; and (4) a processing part for mixing the first and second liquid by the contracted multilayer flow in the funnel-like part.