To prevent impartment of a sense of unease and an unpleasant feeling to an operator, and to indicate so that the operator can properly perform shift operation to a sub-transmission by restraining a shock caused by the shift operation by the sub-transmission to the possible minimum level.
When detecting whether or not a travel state of a work vehicle is a shift allowable state being a stopping state or a low speed travel state lower than a preset speed, and when detecting that the travel state is not the shift allowable state, shift operation of a sub-transmission is checked, and when detecting that the travel state is not the shift allowable state, and when the shift operation of the sub-transmission is commanded, deceleration operation information is indicated for shifting a main transmission to a neutral shift state or a low speed shift state being the low speed travel state.
NAKA TAMAKI
NAKAJIMA TETSUYA
