A method of controlling a motor having windings of a plurality of phases includes an estimation step of calculating a current vector norm from d-axis current and q-axis current flowing in the motor, calculating power loss from the current vector norm and the entire heat resistance of the motor, and estimating the maximum temperature of the windings of the plurality of phases based on the power loss and a transfer function having first or higher-order transfer characteristics, in the case where the motor is in a low rotation state, and a limiting step of limiting input power based on the maximum temperature estimated in the estimation step.