A controlling apparatus of a hybrid vehicle comprising a motor generator that is mechanically connected to an internal combustion engine and that can generate power in response to rotation of the internal combustion engine and provide torque to the internal combustion engine, the controlling apparatus comprising: a rotation information acquiring unit that acquires rotation information of the motor generator with a higher resolution than rotation information of the internal combustion engine; and an assist determining unit that makes a determination regarding start assist by the motor generator based on the rotation information of the motor generator, wherein the assist determining unit judges whether the starting of the internal combustion engine is completed and whether the rotational speed of the motor generator is equal to or smaller than the assist permission rotational speed based on the rotation information of the motor generator and accepts the start assist when the starting of the internal combustion engine is completed, the rotational speed of the motor generator s equal to or smaller than the assist permission rotational speed, and the throttle opening corresponding to an accelerator operation of a driver is smaller than an assist permission lower limit, permits the start assist when the starting of the internal combustion engine is completed, the rotational speed of the motor generator is equal to or smaller than the assist permission rotational speed, and the throttle opening corresponding to the accelerator operation of the driver is equal to or greater than the assist permission lower limit, wherein the controlling apparatus further comprises a torque controlling unit that increases the torque provided to the internal combustion engine by the motor generator, at a rate equal to or smaller than a prescribed time rate of change when the start assist is permitted, and wherein the torque controlling unit increases, in a stepwise manner, the torque provided to the internal combustion engine by the motor generator. a rotation information acquiring unit that acquires rotation information of the motor generator with a higher resolution than rotation information of the internal combustion engine; and an assist determining unit that makes a determination regarding start assist by the motor generator based on the rotation information of the motor generator, wherein the assist determining unit judges whether the starting of the internal combustion engine is completed and whether the rotational speed of the motor generator is equal to or smaller than the assist permission rotational speed based on the rotation information of the motor generator and accepts the start assist when the starting of the internal combustion engine is completed, the rotational speed of the motor generator s equal to or smaller than the assist permission rotational speed, and the throttle opening corresponding to an accelerator operation of a driver is smaller than an assist permission lower limit, permits the start assist when the starting of the internal combustion engine is completed, the rotational speed of the motor generator is equal to or smaller than the assist permission rotational speed, and the throttle opening corresponding to the accelerator operation of the driver is equal to or greater than the assist permission lower limit, wherein the controlling apparatus further comprises a torque controlling unit that increases the torque provided to the internal combustion engine by the motor generator, at a rate equal to or smaller than a prescribed time rate of change when the start assist is permitted, and wherein the torque controlling unit increases, in a stepwise manner, the torque provided to the internal combustion engine by the motor generator.