The hybrid drive device of the present invention includes a selectable one-way clutch 12 that includes a rotational plate that is capable of receiving the reaction torque of an internal combustion engine and that is provided to a power split mechanism, and that can be changed over between: a locked mode in which, in the state of receiving the reaction torque, positive rotation of the rotational plate is prevented while negative rotation of the rotational plate in the direction opposite to the positive rotation is permitted; and a free mode in which, in the state of receiving the reaction torque, the positive rotation and the negative rotation of the rotational plate are both permitted. And, when misfiring of the internal combustion engine occurs, the selectable one-way clutch is kept in the free mode.