A vehicle braking device includes: a stroke simulator for generating a hydraulic pressure corresponding to a brake operation in a hydraulic chamber, the stroke simulator having a cylinder part and a piston part for sliding through the inside of the cylinder part in conjunction with a brake operation of a brake pedal; a booster mechanism having an input part directly pressed by the piston part or pressed by a spring interposed between the input part and the piston part in conjunction with the sliding of the piston part, and thereby moved in sliding fashion through the inside of the cylinder, and a hydraulic pressure generating part for generating a first hydraulic pressure corresponding to the movement of the input part based on the hydraulic pressure of an accumulator; and a wheel cylinder for applying a braking force to a vehicle wheel on the basis of the first hydraulic pressure.