PURPOSE: To trigger an insertion preventing device without being influenced by the fluctuation of battery voltage while regulating the displacement speed of a closing member without measuring the current of a motor.

CONSTITUTION: A closing member driving device for an automobile has a rotating speed regulator 15 for supplying an operating signal Xsiell which is the drift function of the actual rotating speed fist to the target rotating speed fsoll of a driving motor 11, a regulator 16 for changing feed voltage, supplied to the driving motor 11, depending on the operating signal of the rotating speed regulator 15, and an evaluating device 17 for detecting the start of insertion on the basis of a signal depending on the operating signal of the rotating speed regulator 15 so as to trigger an insertion preventing device 18.