Provided is an Al—Mg alloy plate for molding, having excellent press formability, little stretcher strain (SS) mark generation, and not generating any new issues such as reduced bending properties as a result of age-hardening at room temperature, while using more accurate and simple structural indicators. As a result, the Al—Mg aluminum alloy plate comprising a specific composition including Cu has a plate structure having an average particle diameter of 0.5-6.0 nm in a minute particle (cluster) particle distribution measured using an X-ray scattering method, controls the volume fraction to at least 0.03%, is unlikely to have serration, and suppresses SS mark generation during press forming.