A control apparatus for an internal combustion engine comprising a rotary electric machine which has a switching element group (131, 132) in each of one arm and another arm and which is configured to control the switching element group to realize a control state which allows output of control torque for controlling a crank stop position of the internal combustion engine and a power generation state which allows power generation by power of the internal combustion engine, said control apparatus comprising: a first determining device configured to determine whether or not it is in a torque demand state in which the number of revolutions of the internal combustion engine is less than a predetermined number of revolutions and in which it is required to output the control torque to the rotary electric machine, if there is a demand for stopping the internal combustion engine; a second determining device configured to determine whether or not required control torque, which is the control torque required for the rotary electric machine, is less than a predetermined threshold value, if it is determined to be in the torque demand state; a first controlling device configured to control the switching element group in the one arm to realize the control state and to control the switching element group in the other arm to realize the power generation state, if it is determined that the required control torque is less than the predetermined threshold value; a second controlling device configured to control the switching element groups in both the one arm and the other arm to realize the control state, if it is determined that the required control torque is greater than the predetermined threshold value; and a threshold changing device configured to change the predetermined threshold value to increase with increasing number of revolutions of the internal combustion engine. a first determining device configured to determine whether or not it is in a torque demand state in which the number of revolutions of the internal combustion engine is less than a predetermined number of revolutions and in which it is required to output the control torque to the rotary electric machine, if there is a demand for stopping the internal combustion engine; a second determining device configured to determine whether or not required control torque, which is the control torque required for the rotary electric machine, is less than a predetermined threshold value, if it is determined to be in the torque demand state; a first controlling device configured to control the switching element group in the one arm to realize the control state and to control the switching element group in the other arm to realize the power generation state, if it is determined that the required control torque is less than the predetermined threshold value; a second controlling device configured to control the switching element groups in both the one arm and the other arm to realize the control state, if it is determined that the required control torque is greater than the predetermined threshold value; and a threshold changing device configured to change the predetermined threshold value to increase with increasing number of revolutions of the internal combustion engine.