A travel driving apparatus of a vehicle, comprising: a first electrical motor for driving either one of a front wheel and a rear wheel of a vehicle; a transformer for transforming voltage of power supplied from a battery mounted on the vehicle and supplying power to the first electrical motor, wherein maximum output power of the transformer is limited based on a temperature condition; a second electrical motor for driving the other one of the front wheel and the rear wheel of the vehicle, the second electrical motor being supplied with power from the battery not via the transformer; an internal combustion engine mounted on the vehicle and configured to drive the one of the wheels and a generator mounted on the vehicle, the generator being configured to generate power to be supplied to the battery, the first electrical motor, and/or the second electrical motor; a required driving-torque computing section for computing a required travel driving torque of the vehicle; and a distribution ratio computing section for computing a distribution ratio by which the required travel driving torque is distributed into a travel driving torque of the front wheel and a travel driving torque of the rear wheel based on a travelling condition of the vehicle, characterized by further comprising: a starting determination section for performing starting determination of the internal combustion engine based on the required travel driving torque and the distribution ratio, wherein the generator is configured to start the internal combustion engine with power supplied from the battery via the transformer and, on the other hand, supply power generated by being driven by the internal combustion engine to the battery via the transformer, the distribution ratio computing section is configured to set the distribution ratio based on power obtained by subtracting power of the generator needed for starting the internal combustion engine from the maximum output power of the transformer when the vehicle is travelling with the internal combustion engine being stopped, and the starting determination section is configured to start the internal combustion engine to begin power generation at the generator upon judging that the distribution ratio cannot be achieved. a first electrical motor for driving either one of a front wheel and a rear wheel of a vehicle; a transformer for transforming voltage of power supplied from a battery mounted on the vehicle and supplying power to the first electrical motor, wherein maximum output power of the transformer is limited based on a temperature condition; a second electrical motor for driving the other one of the front wheel and the rear wheel of the vehicle, the second electrical motor being supplied with power from the battery not via the transformer; an internal combustion engine mounted on the vehicle and configured to drive the one of the wheels and a generator mounted on the vehicle, the generator being configured to generate power to be supplied to the battery, the first electrical motor, and/or the second electrical motor; a required driving-torque computing section for computing a required travel driving torque of the vehicle; and a distribution ratio computing section for computing a distribution ratio by which the required travel driving torque is distributed into a travel driving torque of the front wheel and a travel driving torque of the rear wheel based on a travelling condition of the vehicle, characterized by further comprising: a starting determination section for performing starting determination of the internal combustion engine based on the required travel driving torque and the distribution ratio, wherein the generator is configured to start the internal combustion engine with power supplied from the battery via the transformer and, on the other hand, supply power generated by being driven by the internal combustion engine to the battery via the transformer, the distribution ratio computing section is configured to set the distribution ratio based on power obtained by subtracting power of the generator needed for starting the internal combustion engine from the maximum output power of the transformer when the vehicle is travelling with the internal combustion engine being stopped, and the starting determination section is configured to start the internal combustion engine to begin power generation at the generator upon judging that the distribution ratio cannot be achieved. a starting determination section for performing starting determination of the internal combustion engine based on the required travel driving torque and the distribution ratio, wherein the generator is configured to start the internal combustion engine with power supplied from the battery via the transformer and, on the other hand, supply power generated by being driven by the internal combustion engine to the battery via the transformer, the distribution ratio computing section is configured to set the distribution ratio based on power obtained by subtracting power of the generator needed for starting the internal combustion engine from the maximum output power of the transformer when the vehicle is travelling with the internal combustion engine being stopped, and the starting determination section is configured to start the internal combustion engine to begin power generation at the generator upon judging that the distribution ratio cannot be achieved.