Abstract: In an assembly comprising a brake master cylinder unit and a dash panel of a vehicle disclosed herein, the electric motor may be fixed to a body of the brake master cylinder unit such that a rotation axis of the electric motor extends along a vehicle-width direction. By fixing the electric motor such that the rotation axis extends along the vehicle-width direction, an overall height of the cylinder unit may be lowered. A position where the pushrod is fixed to the cylinder unit can be lowered, and a position of a pivot of the brake pedal (a connection point between the brake pedal and the dash panel) can also be lowered. As a result, the brake pedal (a pedal arm) can be shortened and weight(s) of part(s) related to the cylinder unit (the pedal arm) can be reduced.