An apparatus and a method are for generating a flattening x-ray radiation field. The apparatus includes: plurality of electron accelerators for generating high-energy electron beam current; and a common target unit including a vacuum target chamber, a target and plurality of input connectors. The plurality of input connectors are connected to one side of the vacuum target chamber and the target is installed at the other side of the vacuum target chamber opposing the plurality of input connectors, the axes of which intersect in pairs at one point in an predetermined included angle. The plurality of electron accelerators are connected to the plurality of input connectors.