A motor control unit or a semiconductor integrated circuit device for an air conditioner is provided. The motor control unit includes a current detector that detects a coil wound current of the permanent magnet motor; a coordinate transformer that transforms the coil wound current detected by the current detector into a d-axis current indicating a magnet flux component and a q-axis current indicating a torque component perpendicular to the magnet flux component; a position estimator that estimates a rotational position of the rotor based on an induced voltage of the permanent magnet motor; a current controller that calculates a command d-axis voltage based on a command d-axis current and the d-axis current detected by the current detector, and that calculates a command q-axis voltage based on a command q-axis current and the q-axis current detected by the current detector; an electrifier controller that electrifies the coil wound based on the command d-axis voltage and the command q-axis voltage; and a start-up controller that detects an oscillation of the rotor during a start-up operation and, if a velocity direction of the oscillation corresponds with a rotational direction of a forcible commutation, the start-up controller starts the forcible commutation so as to start an acceleration of the rotor by following an acceleration pattern.