To provide an active vibration control supporting device capable of appropriately suppressing and controlling vibration transmission so as to prevent a roll natural vibration generated at engine start from being transmitted to a vehicle body.

An ACM_ECU 71 acquires a crank angle before engine start from an engine AT_ECU through the medium of a CAN communication line 207 in a motoring-time roll natural vibration control part 241 when detecting the start of a motoring state. Vibration start timing, input vibration load, vibration frequency and vibration period of the roll natural vibration in conformity with the acquired crank angle before engine start are calculated on the basis of roll natural vibration characteristic data of a data part 241a so as to form a drive current waveform in a drive current operating part 236. Drive control parts 238A, 238B control active control mounts MF, MR based on the drive current waveform.