A performance support device includes a first surface, a second surface, and a flow path. The first surface is configured to face a blow hole of an air reed instrument. The second surface is configured to be displaced from the blow hole. The flow path penetrates from the first surface to the second surface and that is configured to flow an exhaled breath toward the blow hole. A cross-sectional area of the flow path at the first surface is smaller than a cross-sectional area of the flow path at a position displaced from the first surface toward the second surface.