A brake hydraulic pressure control system for a straddle-type vehicle comprising: a substrate in which a flow channel for brake fluid is formed; a motor which includes a stator, a rotor, and an output shaft secured to the rotor, and is a driving source for a pump device provided in the flow channel; a control board of the motor; and a housing which houses therein the control board, and is connected to the substrate, wherein the motor is a brushless motor, and is disposed in a space surrounded by the substrate and the housing, the output shaft is secured to the rotor in such a way that both a first end part and a second end part of the output shaft protrude from the rotor, the motor includes a first bearing which is configured to rotatably support the output shaft at a position between the first end part and the rotor, a second bearing which is configured to rotatably support the output shaft at a position between the second end part and the rotor, and a motor housing which houses therein the stator and the rotor, and holds the first bearing and the second bearing, the brake hydraulic pressure control system further includes a detection mechanism which is configured to detect a rotation state of the output shaft, a first concave part which opens toward the housing is formed in the substrate, and the first bearing of the motor is inserted into the first concave part, wherein the pump device includes a piston which is configured to perform a translatory reciprocating movement characterized in that an eccentric body which is configured to bear an end part of the piston is attached to the output shaft in a region between a portion of the output shaft supported by the first bearing and the first end part, and a region of the output shaft between the portion where the eccentric body is attached and the first end part is free. a substrate in which a flow channel for brake fluid is formed; a motor which includes a stator, a rotor, and an output shaft secured to the rotor, and is a driving source for a pump device provided in the flow channel; a control board of the motor; and a housing which houses therein the control board, and is connected to the substrate, wherein the motor is a brushless motor, and is disposed in a space surrounded by the substrate and the housing, the output shaft is secured to the rotor in such a way that both a first end part and a second end part of the output shaft protrude from the rotor, the motor includes a first bearing which is configured to rotatably support the output shaft at a position between the first end part and the rotor, a second bearing which is configured to rotatably support the output shaft at a position between the second end part and the rotor, and a motor housing which houses therein the stator and the rotor, and holds the first bearing and the second bearing, a first bearing which is configured to rotatably support the output shaft at a position between the first end part and the rotor, a second bearing which is configured to rotatably support the output shaft at a position between the second end part and the rotor, and a motor housing which houses therein the stator and the rotor, and holds the first bearing and the second bearing, the brake hydraulic pressure control system further includes a detection mechanism which is configured to detect a rotation state of the output shaft, a first concave part which opens toward the housing is formed in the substrate, and the first bearing of the motor is inserted into the first concave part, wherein the pump device includes a piston which is configured to perform a translatory reciprocating movement an eccentric body which is configured to bear an end part of the piston is attached to the output shaft in a region between a portion of the output shaft supported by the first bearing and the first end part, and a region of the output shaft between the portion where the eccentric body is attached and the first end part is free.