A braking device including: a loading plate; a pair of front wheels and a pair of rear wheels; a handle provided with clamping units; buffer units installed at the loading plate; and a braking unit that includes: a plurality of engaging grooves formed along a rim of a circular recesses; a brake bar disposed between the rear wheels; an actuating link supported by the brake bar and connected to a hinge portion; a connecting link connected to the actuating link by an interlocking bar; a connecting spring connected to the brake bar and the interlocking bar, a push switch fixed at an upper side of the connecting link, and a foot brake pedal fixed at an upper side of the push switch and has a top surface exposed at the top of the loading plate.