A damping-force-adjustable-damper control device includes a target damping force setting unit which sets target damping force, a stroke position detecting unit which detects a stroke position of the damping-force adjustable damper, a stroke speed calculating unit which calculates a stroke speed, and a target output calculating unit which calculates a target output value to be output to the damping-force adjustable damper in accordance with an obtained target damping force and an obtained stroke speed. The control device also includes a processing-period setting unit which sets the processing periods of the stroke speed calculating unit and the target output calculating unit in accordance with a resonant frequency of unsprung mass, and which sets the processing period of the target damping force setting unit to be longer than the processing periods of the stroke speed calculating unit and the target output calculating unit in accordance with a resonant frequency of sprung mass.