An influence component N30m of every 30 degrees in a 30 degree rotation speed N30 base as time required for 30 degree rotation of a crankshaft is calculated by using a frequency characteristic of an influence given to a rotation fluctuation of a crankshaft by output torque output from a motor, which is calculated by using a mechanical model and an amplitude P and a phase q at a time of vibration control by the motor, a determination duration T30j is calculated by subtracting an influence component T30m as an inverse number of this from 30 degree duration T30, and misfire of an engine is determined by comparing the calculated determination duration T30j with a threshold value Tref. Thereby, misfire of the engine outputting power to a post-stage via a damper can be determined more reliably and accurately.