A metal pattern forming method according to an embodiment includes forming a metal film on a surface of a substrate by an electroless plating method, the substrate including a first layer including a protrusion and a recess, and a film thickness of the metal film being a half or more of a width of the recess; and performing wet etching, the metal film in the recess removed by the wet etching and the metal film on the protrusion remained after the wet etching.