A drive assistance device for a wheel chair having a drive motor, a driving wheel, a sensor means which is designed such that a driving force manually induced into a driving wheel is detected, and a control unit, designed such that the drive motor is controlled to drive the driving wheel in accordance with a drive assistance degree depending on the driving force manually induced into the driving wheel, wherein the control unit comprises an anti-rollback operational mode in which it is adapted to control the drive motor such that an unintended rolling of the driving wheel is avoided. The invention also relates to a wheel chair having such a drive assistance device.