The present invention relates to a spray boom structure comprising a central section (2) and two lateral masts (3, 3 ') arranged on either side of the central section (2) and each formed of at least one section, each section (4) having a prismatic shape with triangular section, with a continuously decreasing height from one end to the other of the section (4) considered and consisting of a tubular assembly comprising a top longitudinal tube and two tubes lower longitudinal members (6) and connecting elements (7, 7 ') forming tie rods and struts, extending between the top tube and the two lower tubes (6). Ramp structure characterized in that the spacing between the two lower tubes (6) varies similarly to the height of one longitudinal end to the other of the section (4) concerned.
