A pushing force-actuated braking device includes an annular housing that houses a brake disc, a braking piston, plural braking elements, and a brake-releasing piston. When only the braking piston is under the action of a fluid, the braking piston applies an axial pushing force to the brake disc such that the brake disc is kept at a braking position jointly by the braking piston and the braking elements. When only the brake-releasing piston is under the action of a fluid, the brake-releasing piston applies an opposite pushing force to the brake disc to keep it at a brake-releasing position. Should the fluid acting on the braking piston fail, the force of the braking elements still enables the brake disc to produce a braking effect. The pushing force-actuated braking device has a modular design to facilitate assembly and disassembly. A rotary table using the braking device is also provided.