A control target for a control device (10) is a vehicle drive device (1) including a rotating electrical machine (MG), and the control device (10) includes: an actual rotational speed obtaining part (14) that obtains an actual rotational speed (Nm) which is an actual rotational speed of the rotating electrical machine (MG); an actual torque obtaining part (15) that obtains actual torque (Tm) which is actual torque of the rotating electrical machine (MG); and a determining part (16) that determines a state of the rotating electrical machine (MG). The determining part (16) determines that the state of the rotating electrical machine (MG) is a negative torque abnormality, when the actual torque (Tm) has a negative value smaller than a torque threshold value (THt) set based on a relationship between the actual rotational speed (Nm) and target torque (Tmt) of the rotating electrical machine (MG).