To provide a flow straightening member for a showcase capable of simplifying a manufacture process without easily letting a reinforcing member be exfoliated, and its manufacturing method.

By alternately laminating a plurality of plate members 11 and a plurality of corrugated bend members 12, the flow straightening member 10 having a flow straightening function equivalent to a conventional honeycomb structure is manufactured, and it is manufactured more easily than the honeycomb structure. In this case, since the flow straightening member 10 is formed by arranging the reinforcing member 13 whose thickness dimension is larger than the plate members 11 on one end side in the laminating direction of the respective plate members 11 and the respective bend members 12 and integrally joining the respective plate members 11, the respective bend members 12 and the reinforcing member 13, the reinforcing member 13 is integrally joined by the same process as the respective plate members 11 and the respective bend members 12, and adhesion defects are generated less compared to the case of separately adhering the reinforcing member in the post process.