A control device for a working vehicle, the device including a circuit (HC1) for traveling constructed as a closed circuit by interconnecting a variable displacement hydraulic pump (2) driven by an engine (1) and a variable displacement hydraulic motor (3), a circuit (HC2) for working having a hydraulic pump (4) for working driven by the engine (1) and also having hydraulic actuators (114, 115) for working driven by pressurized oil from the hydraulic pump (4), a relief valve (14) for relieving pressurized oil in the circuit (HC1) for traveling, rotational speed control sections (10, 18) for controlling the speed of the engine according to the amount of operation of an accelerator pedal (9), condition detection sections (21, 22) for detecting the vehicle being simultaneously in both a highload travel condition and a high load work condition, and a speed limit section (10) which, when the condition detection sections (21, 22) detect that the vehicle is simultaneously in both high load travel and high load work conditions, reduces an upper limit value (Nlim) of the engine speed.