A drive control apparatus in which the target torque which is a target value of an output torque of the prime mover for driving a vehicle, is calculated, and the output torque control is performed so that the output torque of the prime mover coincides with the target torque, is provided. An estimated output torque which is an estimated value of the actual output torque of the prime mover, is calculated, and the torque difference accumulated value which approximates a time-integration value of a torque difference between the target torque and the estimated output torque, is calculated. It is determined that an abnormality has occurred in the output torque control when the torque difference accumulated value exceeds a determination threshold value which is set to a constant value.