A vehicle-mounted drive control apparatus capable of effecting boosted escape running while preventing burnout when a reversible motor driven by way of a transistor bridge circuit encounters an abnormal load. A motor driven by a transistor bridge circuit reversibly drives a moving body between a reverse limit stopper and a forward limit stopper. A variable resistance produces an output signal related to the position of the moving body, and calibration information is read at the positions of the reverse limit position and forward limit position and saved from a microprocessor to a nonvolatile data memory in advance. When during normal drive running of the motor the motor stops at an intermediate position between the forward limit stopper and the reverse limit stopper, escape drive is carried out by the motor being driven alternately with a boosted current above its rated current and a resting current which is small or 0.