The flow path structure includes a flow path introducing fluid from an inlet to an outlet, and a flow velocity control structure provided in a portion between the inlet and the outlet in the flow path to reduce difference in flow velocity that the fluid flowing into the flow path has in a direction intersecting with a flow direction of the fluid. The flow velocity control structure includes, in the direction intersecting with the flow direction, plural flow velocity control members provided alternately with spaces through which the fluid passes. The flow velocity control members have different sizes from each other, the sizes increasing as the flow velocity of the fluid at areas, in the direction intersecting with the flow direction, where the respective flow velocity control members are provided increases.