The method for producing a metal member includes a step of preparing a first member made of a first metal, a second member made of a second metal, and a third member made of a third metal, and a step of joining the first member and the second member via the third member. The step of joining includes a step of heating the first member, the second member, and the third member by stacking the first member, the third member, and the second member in this order and relatively rotating the first member about an axis of rotation, while pressing the first member against the third member, without changing a positional relationship, and a step of cooling the first member, the second member, and the third member heated, with the members being in the stacked state.