To enhance the operability and productivity of an actuation control device for a boom-equipped working vehicle by enabling a boom to move diagonally vertically through cooperative actuation achieved by a single operation.

When a triaxial operating lever 31 is operated during the cooperative actuation, the actuation of a boom derricking drive means 5 and a boom telescoping drive means 6 is controlled based on a calculated amount of drive corresponding to the oscillation of the triaxial operating lever 31 about a first or second axis, so that the boom end 3a moves horizontally within a boom derricking plane. The actuation of the boom derricking drive means 5 and the boom telescoping drive means 6 is controlled based on a calculated amount of drive corresponding to the oscillation of the lever about the second or first axis, so that the boom end moves vertically within the boom derricking plane. When the triaxial operating lever 31 is operated to oscillate about the first and second axes at the same time, the boom end moves diagonally vertically within the boom derricking plane. Thus, the operability or productivity of the working vehicle is made higher than when the boom cannot be moved diagonally vertically by the cooperative actuation, as is the case with devices of the prior art.