PROBLEM TO BE SOLVED: To provide a lifting/lowering device of a working vehicle that is compatible on the occurrence of the cause of preventing the lowering of a working machine connected to the rearward of a traveling machine body, and capable of quickly lowering and operating the working machine when the cause is eliminated.SOLUTION: A lifting/lowering device of a working vehicle includes: a hydraulic cylinder 38 for lifting/lowering and operating a working machine 3 by the expansion and contraction thereof a solenoid valve 43 for controlling the lowering of the working machine 3 through a hydraulic cylinder 38 detection means 71 for detecting a lifting/lowering height of the working machine 3 and a control unit 69 for controlling the lowering of the working machine 3 by the current supply control to the solenoid valve 43. The control unit 69 intermittently supplies current to the solenoid valve 43 or reduces the current supplied to the solenoid valve 43 being a proportional control valve, when the condition of the lifting/lowering of the working machine 3 stopped more than a predetermined time is detected by detection means 71 during supplying the current to the solenoid valve 43 so that the working machine 3 is lowered and operated.COPYRIGHT: (C)2015,JPO&INPIT【課題】 走行機体の後部に連結された作業機の下降を妨げる原因が生じた場合に対応可能で、該原因が無くなった場合、迅速に作業機を下降作動させることが可能な作業車両の昇降装置を提供することを課題とする。【解決手段】 作業機3を伸縮によって昇降作動させる油圧シリンダ38と、油圧シリンダ38を介して前記作業機3の下降を制御する電磁弁43と、該作業機3の昇降高さを検出する検出手段71と、前記電磁弁43への電流供給制御によって上記作業機3の下降を制御する制御部69とを備え、該制御部69は、作業機3を下降作動させるように上記電磁弁43に電流を供給している最中に、前記作業機3が所定時間以上昇降停止している状態が上記検出手段71によって検出された場合には、前記電磁弁43に間欠的に電流を供給するか或いは比例制御弁である電磁弁43に供給する電流を低下させる。【選択図】 図6
