In a hybrid vehicle, noise occurrence caused in a rectangular wave control of a motor is restricted when a motor running mode is selected with a converter boosting limit applied. A motor controller for a hybrid vehicle mounted with an internal combustion engine and a motor as power sources is provided. The motor controller includes a converter capable of boosting a voltage supplied from a power supply device; an inverter which converts an output voltage of the converter to an AC voltage and applies the AC voltage to the motor; and a control unit which controls the inverter to drive the motor by switching between two or more control modes. When a running mode to drive the vehicle by a motor power alone is selected with a boost limit applied to the output voltage of the converter and when the motor is driven in a rectangular wave control mode or an overmodulation PWM control mode, the control unit raises the output voltage of the converter higher than a boost limit value and controls the inverter such that the control mode is switched to drive the motor in a sinusoidal PWM control mode.