Various works of a tractor or wheel loader that require frequent operations of start, stop, and switching between the forward drive and reverse drive that are repeated alternately can be performed very easily. The control apparatus comprises a speed change sensor that detects the step-on amount of a speed change pedal, an actuator that regulates the swash plate angle of a hydraulic pump based on the detection value of the speed change sensor, a transmission output unit rotation sensor that detects the revolution speed of an output shaft, and a control unit. The control unit performs control such that when the speed change pedal is not stepped on, a brake is applied to the travel wheels and both the forward drive clutch and the reverse drive clutch are disengaged, and also performs control such that when the transmission drive output detected with the transmission output unit rotation sensor is not more than that the forward-reverse drive switching speed, either the forward drive clutch or the reverse drive clutch is engaged as the speed change pedal is stepped on. When the engagement of the forward drive clutch or reverse drive clutch is confirmed, the brake of the travel wheels is released.