Plating apparatus and air bubble removing method of plating apparatus

Provided is a technique that ensures the suppressed deterioration of plating quality of a substrate due to air bubbles that remain on a surface to be plated of the substrate.A plating apparatus 1000 includes a plating tank 10, a substrate holder 30, a rotation mechanism 40, and an elevating mechanism 50. The plating tank 10 is configured to accumulate a plating solution and include an anode 11 arranged inside the plating tank. The substrate holder 30 is arranged above the anode and configured to hold a substrate as a cathode such that a surface to be plated of the substrate faces downward. The substrate holder includes a ring 31 projecting below an outer peripheral edge of the surface to be plated of the substrate. The rotation mechanism 40 is configured to rotate the substrate holder. The elevating mechanism 50 is configured to elevate the substrate holder. The ring has a lower surface, and at least one protrusion 35 projecting toward a lower side is arranged on a part of the lower surface.