A bed frame includes outer lateral and longitudinal bar units, each having a first end and a second end. Each of first, second, third, and fourth longitudinal bar units includes an upper longitudinal bar and a lower longitudinal bar. The first ends of the first and second longitudinal bar units are rotatably connected with each other. The first ends of the third and fourth longitudinal bar units are rotatably connected with each other. Of each respective longitudinal bar unit, the second end of the upper longitudinal bar is movably connected with the first or second end of a corresponding lateral bar unit, and the second end of the lower longitudinal bar is fixedly connected with the first or second end of the corresponding lateral bar unit.