A motor controller includes: a rotation speed measurement portion that measures a rotation speed of a motor; and an energization method switching portion that switches an energization method so that the motor is driven by a 120-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion is less than or equal to a predetermined threshold value, and the motor is driven by a 150-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion exceeds the predetermined threshold value.