In apparatus and method for controlling a rotation speed of a brushless motor, the rotation speed of the rotor is lowered by a predetermined gradient for the rotation speed of the rotor to be reached to a present target value of the rotation speed of the rotor when the rotor of the motor is rotating at a previous target value of the rotor of the motor previously calculated and the present target value of the rotor of the motor is lower than the previous target value thereof at which the rotor of the motor is rotating. The predetermined gradient is, for example, 100% per unit time.