The invention discloses a novel flat car braking device. The novel flat car braking device comprises an operation rod, connecting rods, a brake pad and a locking device. The first connecting rod is fixed to the lower end of a main frame of a flat car. The second connecting rod is fixed to the operation rod. The brake pad is located above a wheel. The brake pad makes contact with and rubs with the wheel through loosening of the operation rod. The locking device is connected between an axle and the operation rod. The novel flat car braking device is easy and convenient to operate and easy to manufacture. No special limitation exists for material selection. The braking device meets the requirement that the small flat car is parked at any time or parked on a slope, and safety accidents are avoided; and meanwhile, the work efficiency can be improved, and the construction cost is reduced.