A travel control apparatus for working vehicle, comprising: a first circuit for traveling, formed through a closed circuit connection of a variable displacement hydraulic pump and a variable displacement hydraulic motor, that comprises a motor control unit that controls a displacement of the hydraulic motor; a second circuit for working that drives a work hydraulic actuator by pressure oil from a work hydraulic pump; and a maximum value control unit that controls a maximum displacement of the hydraulic motor in accordance with load pressure (Pf) in the second circuit, wherein: when a load pressure (Pf) in the second circuit exceeds a first predetermined value (Ps), the maximum value control unit decreases the maximum displacement to a minimum limit corresponding to a maximum load pressure (Pr) in the second circuit within a predetermined increment (ΔP) of the load pressure (Pf) from the first predetermined value (Ps), characterized in that the load pressure (Pf) with the predetermined increment (ΔP) is smaller than the maximum load pressure (Pr) in the second circuit; and the work hydraulic actuator includes a bucket cylinder that drives a bucket and an arm cylinder that drives an arm for supporting the bucket; and the first predetermined value (Ps) is correlated with a maximum value of the bucket operation range(Rb) and set in advance to the maximum load pressure to be generated by drive of the bucket cylinder. a first circuit for traveling, formed through a closed circuit connection of a variable displacement hydraulic pump and a variable displacement hydraulic motor, that comprises a motor control unit that controls a displacement of the hydraulic motor; a second circuit for working that drives a work hydraulic actuator by pressure oil from a work hydraulic pump; and a maximum value control unit that controls a maximum displacement of the hydraulic motor in accordance with load pressure (Pf) in the second circuit, wherein: when a load pressure (Pf) in the second circuit exceeds a first predetermined value (Ps), the maximum value control unit decreases the maximum displacement to a minimum limit corresponding to a maximum load pressure (Pr) in the second circuit within a predetermined increment (ΔP) of the load pressure (Pf) from the first predetermined value (Ps), characterized in that the load pressure (Pf) with the predetermined increment (ΔP) is smaller than the maximum load pressure (Pr) in the second circuit; and the work hydraulic actuator includes a bucket cylinder that drives a bucket and an arm cylinder that drives an arm for supporting the bucket; and the first predetermined value (Ps) is correlated with a maximum value of the bucket operation range(Rb) and set in advance to the maximum load pressure to be generated by drive of the bucket cylinder. when a load pressure (Pf) in the second circuit exceeds a first predetermined value (Ps), the maximum value control unit decreases the maximum displacement to a minimum limit corresponding to a maximum load pressure (Pr) in the second circuit within a predetermined increment (ΔP) of the load pressure (Pf) from the first predetermined value (Ps), characterized in that the load pressure (Pf) with the predetermined increment (ΔP) is smaller than the maximum load pressure (Pr) in the second circuit; and the work hydraulic actuator includes a bucket cylinder that drives a bucket and an arm cylinder that drives an arm for supporting the bucket; and the first predetermined value (Ps) is correlated with a maximum value of the bucket operation range(Rb) and set in advance to the maximum load pressure to be generated by drive of the bucket cylinder.