Abstract: An electron beam 3D printing machine, comprising a chamber for generating and accelerating an electron beam and an operating chamber in which a metal powder is melted, with the consequent production of a three-dimensional product. The chamber for generating and accelerating an electron beam houses means for generating an electron beam and means for accelerating the generated electron beam, while the operating chamber houses at least one platform for depositing the metal powder, metal powder handling means and electron beam deflection means. The accelerator means for the generated electron beam comprise a series of resonant cavities fed with an alternating signal.