Abstract: A brushless motor driving apparatus having a three-phase brushless motor with three stator windings and a rotator magnet and three rotational position detecting elements. There are also first, second and third amplifiers for amplifying the output signals of the three rotational position detection elements as well as first, second and third subtraction circuits for synthesizing the output signals of the amplifiers. First, second and third current driving circuits provide amplified signals to the three-phase stator windings of the three-phase brushless motor. A pulse generation circuit generates one pulse signal per revolution of the three-phase brushless motor based upon the output signals of the first, second and third amplifiers. An automatic gain control automatically controls the gains of the first, second and third amplifiers in response to the output signals of the first, second and third amplifiers.