In an active anti-vibration supporting device (301), an ACM_ECU (200) for estimating an engine vibration state by using output data from a crank pulse sensor (Sa) and a TDC sensor (Sb) drives a driving unit (41) so as to extend and contract and thereby suppresses the transmission of vibration. The ACM_ECU (200) calculates the number of STGs (S1F) that is a quotient obtained when dividing the phase delay (P1F) of a target current value waveform by an average STG time ((T1)/4) in a first cycle (C1) of engine vibration and the remaining time (P′1F) of the phase delay (P1F), wherein the target current value waveform is used for suppressing the transmission of the engine vibration calculated using the output data from the crank pulse sensor (Sa) and the TDC sensor (Sb). The timing at which the elapse of the STG time equivalent to the number of STGs (S1F) in a third cycle (C3) of the engine vibration in the driving timing of the driving unit has been detected is set as a phase delay reference. Further, after the remaining time (P′1F) has elapsed, the target current value waveform is output.