PURPOSE: To maximize recovery rate of regenerative energy by making a decision whether an automatic transmission is in a highest brake force state or not based on the number of revolution of motor detected through a rotation sensor and down shifting the gear position if the answer is negative.

CONSTITUTION: An inverter 20 is driven with DC output from a battery 24 based on a PWM signal fed from a motor controller MC 18. A motor 22 is rotated with three-phase VVVF power produced from the inverter 20 thus rotating wheels 16 through an automatic transmission 26. An ECT 28 sets a gear position of the automatic transmission 26 according to a gear position command GC fed from an MC 18 and notifies a current gear position G to the MC 18. Number of revolution (n) of the motor 22 is detected through a rotation sensor 30 and delivered to the MC 18 which makes a decision whether the automatic transmission is in a highest regenerative brake state or not and down shifts the gear position if the answer is negative. According to the constitution, a good brake feeling is realized and recovery of energy is maximized.