FLOW PASSAGE STRUCTURE OF FUEL CELL SYSTEM

Provided is a flow passage structure that is employed in a fuel cell system and includes a hydrogen gas pipe, a hydrogen off-gas pipe, a supply pipe, a lead-out pipe, and a plurality of junctions. The lead-out pipe includes a first wall located between an inner wall and a central axis of the supply pipe, a second wall connected to the first wall and located between the first wall and the central axis, and a first region surrounded by the first wall and the second wall, and is configured such that a second region between the inner wall and the first wall and a third region on the side of the central axis from the second wall communicate with each other. At the junctions, the first region and a leading end part of the hydrogen gas pipe communicate with and connect to each other.