The vibration damping control device which performs damping of vibration of a vehicle body through a driving output control of a diesel vehicle in accordance with the present invention comprises a compensation component computing portion which computes a compensation component which compensates a wheel torque to suppress an amplitude of vehicle body vibration; and a control gain determining portion which determines a control gain for the compensation component, wherein, at a time point of reversion of the sign of the value of the compensation component, the control gain determining portion decreases the control gain when, before that time point, the value of the compensation component has deviated from a restriction range for variation of a fuel injection quantity determined based on engine operational condition, and increases the control gain when the value of the compensation component has not deviated from a restriction range for variation of a fuel injection quantity. Thereby, in the execution of the restriction of the fuel injection quantity variation, the wave form of the compensation component of the vibration damping control is maintained, and also, the effect of the vibration damping control becomes as large as possible.