The invention provides a motor drive control device and a motor drive control system which, even when two Hall elements are used, can easily control the driving of a 3-phase brushless motor without separately requiring a control unit having a complicated algorithm. A motor drive control device (1) is for controlling the driving of a brushless motor (51) that includes a stator (52) having 3-phase drive coils and a rotor (53) having plural magnetic poles, and the motor drive control device (1) includes Hall elements (2u, 2v), a drive signal determining unit (7) and an output circuit (8). The Hall elements (2u, 2v) are disposed in positions apart from each other by an electric angle of 120 degrees and output position detection signals (Hu, Hv) representing the position of the rotor (53) with respect to the stator (52). The drive signal determining unit (7) determines drive signals (SU, SV, SW) for driving the 3-phase drive coils on the basis of the position detection signals (Hu, Hv). The output circuit (8) generates and outputs, to the 3-phase drive coils, the drive signals (SU, SV, SW) that have been determined by the drive signal determining unit (7).