A vehicle gear-shifting control apparatus, comprising: an engine which is mounted to a vehicle and which is configured to generate a travel drive force of the vehicle; a motor which is configured to generate a travel drive force of the vehicle and which is configured to supply a battery with regenerative energy during deceleration of the vehicle; an automatic transmission of which an input shaft is connected to the engine and the motor and an output shaft is connected to a rear wheel and which is configured to subject an input rotation to gear-shifting or speed-changing at a transmission gear ratio corresponding to a shift stage and is configured to output a rotation; a friction brake system which is configured to distribute a braking force to a front wheel and the rear wheel in order to realize braking in accordance with a brake pedal operation by a driver; and a controller which is configured to execute, during deceleration of the vehicle during which the friction brake system is distributing a braking force to the front wheel and the rear wheel, regeneration control of imparting a regenerative braking torque to the rear wheel by causing the motor to perform a regeneration operation and gear-shifting control of causing the automatic transmission to perform a shift-down by outputting a shift-down signal in accordance with a rotation speed of the input shaft to the automatic transmission, wherein the controller is configured to increase an input torque of the input shaft of the automatic transmission according to a shift-down of the automatic transmission so that an acceleration fluctuation of the vehicle which accompanies the shift-down equals a target acceleration fluctuation, and when the controller determines an oversteered state of the vehicle during the regeneration control and during a shift-down of the automatic transmission, the controller is configured to increase the input torque of the input shaft of the automatic transmission so that the regenerative braking torque decreases while maintaining the regeneration operation of the motor and the controller is configured to cause the automatic transmission to perform the shift-down in a state where an amount of increase of the input torque of the input shaft in accordance with the shift-down has been increased as compared to an amount of increase of the input torque of the input shaft during a non-determination of an oversteered state. an engine which is mounted to a vehicle and which is configured to generate a travel drive force of the vehicle; a motor which is configured to generate a travel drive force of the vehicle and which is configured to supply a battery with regenerative energy during deceleration of the vehicle; an automatic transmission of which an input shaft is connected to the engine and the motor and an output shaft is connected to a rear wheel and which is configured to subject an input rotation to gear-shifting or speed-changing at a transmission gear ratio corresponding to a shift stage and is configured to output a rotation; a friction brake system which is configured to distribute a braking force to a front wheel and the rear wheel in order to realize braking in accordance with a brake pedal operation by a driver; and a controller which is configured to execute, during deceleration of the vehicle during which the friction brake system is distributing a braking force to the front wheel and the rear wheel, regeneration control of imparting a regenerative braking torque to the rear wheel by causing the motor to perform a regeneration operation and gear-shifting control of causing the automatic transmission to perform a shift-down by outputting a shift-down signal in accordance with a rotation speed of the input shaft to the automatic transmission, wherein the controller is configured to increase an input torque of the input shaft of the automatic transmission according to a shift-down of the automatic transmission so that an acceleration fluctuation of the vehicle which accompanies the shift-down equals a target acceleration fluctuation, and when the controller determines an oversteered state of the vehicle during the regeneration control and during a shift-down of the automatic transmission, the controller is configured to increase the input torque of the input shaft of the automatic transmission so that the regenerative braking torque decreases while maintaining the regeneration operation of the motor and the controller is configured to cause the automatic transmission to perform the shift-down in a state where an amount of increase of the input torque of the input shaft in accordance with the shift-down has been increased as compared to an amount of increase of the input torque of the input shaft during a non-determination of an oversteered state.