PURPOSE: To obtain an operation apparatus for controlling vertical position of a working machine capable of switching the work mode between the work by the working machine at an engaging position by engaging an operation lever with a stopper and the work by the working machine at a position to pull down the lever below the engaging position without releasing the fixation of the stopper part and the resetting of the position of the stopper part.

CONSTITUTION: This operation apparatus 1 for controlling the vertical position of a working machine is composed of an operation base part 2 held on the main body 80 of a tractor, an operation lever 3 held on the operation base part 2 in a relatively movable state to control the vertical position of a working machine 9 liftably attached to the tractor main body 80, stopper parts 4, 6 held on the operation base part 2 in a state movable in the moving direction of the operation lever 3 and inhibit the movement of the operation lever 3 in a specified direction and a fixing parts 5, 7 to fix the stopper parts 4, 6 to the operation base part 2. The stopper parts 4, 6 have high-resistance parts 40, 60 to hinder the motion of the operation lever 3.